Chapter 4 : The Logic of Boolean Connec6ves. Not all English connec4ves are truth- func4onal

Size: px
Start display at page:

Download "Chapter 4 : The Logic of Boolean Connec6ves. Not all English connec4ves are truth- func4onal"

Transcription

1 Chapter 4 : The Logic of Boolean Connec6ves Not all English connec4ves are truth- func4onal Max was at home because Claire went to the library. Home(max) because WentToLibrary(claire) T T T T F T Hence the English connec6ve because is not truth- func6onal! More examples: while; it s necessary that; in virtue of; for the reason that; explains, etc. 3 1

2 Three Logical Rela4ons: Logical consequence, equivalence, & truth Logical consequence: P is a logical consequence of Q IFF it s impossible for Q to be true while P is false RECALL: This was the nodon of validity of an argument. Logical equivalence: P is logically equivalent to Q IFF it s impossible for Q and P to have different truth- values OR: P is a logical consequence of Q and vice versa! Logical truth: P is a logical truth IFF it s impossible for P to be false (i.e., P is necessarily true, that is, true in every possible/conceivable situa6on). 4 Finessing the general no4on of logical rela4ons Logical consequence! Tautological consequence Logical equivalence! Tautological equivalence Logical truth! Tautological truth Later (star6ng in Chapter 9), we ll introduce even more powerful technical no6ons finessing the general no6on: Logical consequence! FO- consequence Logical equivalence! FO- equivalence Logical truth! FO- validity (or, necessity) 5 2

3 Why finesse? Logical Truth: (single sentence) English Examples Either Obama is taller than his wife or he is not. FOL version would be a tautology: Taller(obama, michelle) V Taller(obama, michelle) More generally in terms of Ps and Qs: P V P Determined solely on the basis of truth- func4onal connec4ves (Taut- Con) If Samuel Clemens is idendcal to Mark Twain, then Mark Twain is idendcal to Samuel Clemens. FOL version would be a First- Order truth or FO- necessity: clemens=twain! twain=clemens (or: if a=b then b=a) Compare in terms of Ps and Qs: If P then Q Determined solely on the basis of TF connec4ves, quan4fiers, and the meaning of the = predicate (FO- Con) All bachelors are unmarried FOL version would be an analy6cal truth or necessity: x (Bachelor(x)! Unmarried(x)) Compare in terms of Ps and Qs: P Determined on the basis of all the above apparatus AND the meanings of all predicates. (Ana- Con) Compare: Tarski- World Necessity (or, TW- necessity): Cube(a) V Tet(a) V Dodec(a) 6 Rela4onship among Necessi4es 7 3

4 Rela4onship among Possibili4es 8 Tautologies A tautology is a logical truth that is true in all possible situa6ons en6rely due to the truth- condi6onal connec6ves it contains and nothing else! Alterna6vely: A tautology is a logical truth whose truth- table contains True in all of its rows under the main connec6ve. (Because of this tautologies are some6mes called Truth- Table- necessity or TT- necessity) Example: If A, B, C are sentences of FOL, then the following is a tautology: (A ( A (B C))) B 9 4

5 Construc4ng TRUTH- TABLES Determine how many dis6nct atomic sentence types there are in order to calculate the number of rows you need for the table. number of rows = 2 n, where n is the number of dis6nct atomic sentences. Law of the Excluded Middle: P V P (Either P is true or its nega6on is true but not both) Set up the reference columns according to the number of dis6nct atomic sentences. (Open Boole) 10 From logical consequence to tautological consequence An FOL sentence P is a tautological consequence of sentences Q n Q m IFF there is no row, in their joint TT, in which Q n Q m are true and P is false: 11 5

6 From logical equivalence to tautological equivalence FOL sentences P and Q are tautologically equivalent IFF there is no row, in their joint TT, in which P and Q have different truth value (i.e., if their truth- tables are exactly the same) 12 Truth- Table vs. Fitch Proof method Tautological rela6ons can be demonstrated by proof methods. Either by actually construc6ng the official proofs in F, Or by using the sogware Fitch s Taut- Con mechanism. Revisit the uses of Taut- con, FO- con, Ana- con mechanisms 13 6

7 Pushing nega4on around Subs4tu4on of equivalents: If P and Q are logically equivalent: P Q then the results of subs6tu6ng one for the other in the context of a larger sentence are also logically equivalent: S(P) S(Q) A sentence is in nega6on normal form (NNF) IFF all occurrences of apply directly to atomic sentences. Any sentence built from atomic sentences using just,, and can be put into NNF by repeated applica6on of the De- Morgan Laws and Double Nega6on. Sentences can ogen be further simplified using the principles of associa6vity, commuta6vity, and idempotence. 14 Associa4vity 1. (Associa6vity of ): P (Q R) (P Q) R P Q R 2. (Associa6vity of ): P (Q R) (P Q) R P Q R 15 7

8 Commuta4vity 3. (Commuta6vity of ): P Q Q P As a result, any rearrangement of the conjuncts of an FOL sentence is logically equivalent to the original. For example, P Q R is equivalent to R Q P. 4. (Commuta6vity of ): P Q Q P As a result, any rearrangement of the disjuncts of an FOLsentence is logically equivalent to the original. For example, P Q R is equivalent to R Q P 16 Idempotence 5. (Idempotence of ): P P P More generally (given Commuta6vity), any conjunc6on with a repeated conjunct is equivalent to the result of removing all but one occurrence of that conjunct. For example, P Q P is equivalent to P Q. 6. (Idempotence of ) P P P More generally (given Commuta6vity), any disjunc6on with a repeated disjunct is equivalent to the result of removing all but one occurrence of that disjunct. For example, P Q P is equivalent to P Q. 17 8

9 Distribu4ve Laws For any sentences P, Q, and R: 1. Distribu6on of over : P (Q R) (P Q) (P R) 2. Distribu6on of over : P (Q R) (P Q) (P R) 18 DNF and CNF A sentence is in disjunc6ve normal form (DNF) if it is a disjunc6on of one or more conjunc6ons of one or more literals. A sentence is in conjunc6ve normal form (CNF) if it is a conjunc6on of one or more disjunc6ons of one or more literals. Distribu6on of over allows you to transform any sentence in nega6on normal form into disjunc6ve normal form. Distribu6on of over allows you to transform any sentence in nega6on normal form into conjunc6ve normal form. Some sentences are in both CNF and DNF: e.g., P Q (why?) 19 9

Tautological equivalence. entence equivalence. Tautological vs logical equivalence

Tautological equivalence. entence equivalence. Tautological vs logical equivalence entence equivalence Recall two definitions from last class: 1. A sentence is an X possible sentence if it is true in some X possible world. Cube(a) is TW possible sentence. 2. A sentence is an X necessity

More information

10/13/15. Proofs: what and why. Proposi<onal Logic Proofs. 1 st Proof Method: Truth Table. A sequence of logical arguments such that:

10/13/15. Proofs: what and why. Proposi<onal Logic Proofs. 1 st Proof Method: Truth Table. A sequence of logical arguments such that: Proofs: what and why Rules of Inference (Rosen, Section 1.6) TOPICS Logic Proofs ² via Truth Tables ² via Algebraic Simplification ² via Inference Rules A sequence of logical arguments such that: each

More information

Introduc)on. CSC 1300 Discrete Structures Villanova University. Villanova CSC Dr Papalaskari 1

Introduc)on. CSC 1300 Discrete Structures Villanova University. Villanova CSC Dr Papalaskari 1 Introduc)on CSC 1300 Discrete Structures Villanova University 1 Discrete Structures Goal: Understand how to use mathema)cs to reason about problems in Computer Sciences: sets and coun)ng func)ons and rela)ons

More information

Discrete Structures. Introduc:on. Examples of problems solved using discrete structures. What is discrete about Discrete Structures?

Discrete Structures. Introduc:on. Examples of problems solved using discrete structures. What is discrete about Discrete Structures? Discrete Structures Introduc:on CSC 1300 Discrete Structures Villanova University Goal: Understand how to use mathema:cs to reason about problems in Computer Sciences: sets and coun:ng func:ons and rela:ons

More information

W3203 Discrete Mathema1cs. Logic and Proofs. Spring 2015 Instructor: Ilia Vovsha. hcp://www.cs.columbia.edu/~vovsha/w3203

W3203 Discrete Mathema1cs. Logic and Proofs. Spring 2015 Instructor: Ilia Vovsha. hcp://www.cs.columbia.edu/~vovsha/w3203 W3203 Discrete Mathema1cs Logic and Proofs Spring 2015 Instructor: Ilia Vovsha hcp://www.cs.columbia.edu/~vovsha/w3203 1 Outline Proposi1onal Logic Operators Truth Tables Logical Equivalences Laws of Logic

More information

Truth-Functional Logic

Truth-Functional Logic Truth-Functional Logic Syntax Every atomic sentence (A, B, C, ) is a sentence and are sentences With ϕ a sentence, the negation ϕ is a sentence With ϕ and ψ sentences, the conjunction ϕ ψ is a sentence

More information

Boolean Algebra. Philipp Koehn. 9 September 2016

Boolean Algebra. Philipp Koehn. 9 September 2016 Boolean Algebra Philipp Koehn 9 September 2016 Core Boolean Operators 1 AND OR NOT A B A and B 0 0 0 0 1 0 1 0 0 1 1 1 A B A or B 0 0 0 0 1 1 1 0 1 1 1 1 A not A 0 1 1 0 AND OR NOT 2 Boolean algebra Boolean

More information

CS1021. Why logic? Logic about inference or argument. Start from assumptions or axioms. Make deductions according to rules of reasoning.

CS1021. Why logic? Logic about inference or argument. Start from assumptions or axioms. Make deductions according to rules of reasoning. 3: Logic Why logic? Logic about inference or argument Start from assumptions or axioms Make deductions according to rules of reasoning Logic 3-1 Why logic? (continued) If I don t buy a lottery ticket on

More information

Announcements. CS311H: Discrete Mathematics. Propositional Logic II. Inverse of an Implication. Converse of a Implication

Announcements. CS311H: Discrete Mathematics. Propositional Logic II. Inverse of an Implication. Converse of a Implication Announcements CS311H: Discrete Mathematics Propositional Logic II Instructor: Işıl Dillig First homework assignment out today! Due in one week, i.e., before lecture next Wed 09/13 Remember: Due before

More information

Outline. Logic. Knowledge bases. Wumpus world characteriza/on. Wumpus World PEAS descrip/on. A simple knowledge- based agent

Outline. Logic. Knowledge bases. Wumpus world characteriza/on. Wumpus World PEAS descrip/on. A simple knowledge- based agent Outline Logic Dr. Melanie Mar/n CS 4480 October 8, 2012 Based on slides from hap://aima.eecs.berkeley.edu/2nd- ed/slides- ppt/ Knowledge- based agents Wumpus world Logic in general - models and entailment

More information

The Calculus of Computation: Decision Procedures with Applications to Verification. Part I: FOUNDATIONS. by Aaron Bradley Zohar Manna

The Calculus of Computation: Decision Procedures with Applications to Verification. Part I: FOUNDATIONS. by Aaron Bradley Zohar Manna The Calculus of Computation: Decision Procedures with Applications to Verification Part I: FOUNDATIONS by Aaron Bradley Zohar Manna 1. Propositional Logic(PL) Springer 2007 1-1 1-2 Propositional Logic(PL)

More information

CS 161: Design and Analysis of Algorithms

CS 161: Design and Analysis of Algorithms CS 161: Design and Analysis of Algorithms NP- Complete I P, NP Polynomial >me reduc>ons NP- Hard, NP- Complete Sat/ 3- Sat Decision Problem Suppose there is a func>on A that outputs True or False A decision

More information

Propositional Calculus: Formula Simplification, Essential Laws, Normal Forms

Propositional Calculus: Formula Simplification, Essential Laws, Normal Forms P Formula Simplification, Essential Laws, Normal Forms Lila Kari University of Waterloo P Formula Simplification, Essential Laws, Normal CS245, Forms Logic and Computation 1 / 26 Propositional calculus

More information

Phil 110, Spring 2007 / April 23, 2007 Practice Questions for the Final Exam on May 7, 2007 (9:00am 12:00noon)

Phil 110, Spring 2007 / April 23, 2007 Practice Questions for the Final Exam on May 7, 2007 (9:00am 12:00noon) Phil 110, Spring 2007 / April 23, 2007 Practice Questions for the Final Exam on May 7, 2007 (9:00am 12:00noon) (1) Which of the following are well-formed sentences of FOL? (Draw a circle around the numbers

More information

Tecniche di Verifica. Introduction to Propositional Logic

Tecniche di Verifica. Introduction to Propositional Logic Tecniche di Verifica Introduction to Propositional Logic 1 Logic A formal logic is defined by its syntax and semantics. Syntax An alphabet is a set of symbols. A finite sequence of these symbols is called

More information

CS206 Lecture 03. Propositional Logic Proofs. Plan for Lecture 03. Axioms. Normal Forms

CS206 Lecture 03. Propositional Logic Proofs. Plan for Lecture 03. Axioms. Normal Forms CS206 Lecture 03 Propositional Logic Proofs G. Sivakumar Computer Science Department IIT Bombay siva@iitb.ac.in http://www.cse.iitb.ac.in/ siva Page 1 of 12 Fri, Jan 03, 2003 Plan for Lecture 03 Axioms

More information

A brief introduction to Logic. (slides from

A brief introduction to Logic. (slides from A brief introduction to Logic (slides from http://www.decision-procedures.org/) 1 A Brief Introduction to Logic - Outline Propositional Logic :Syntax Propositional Logic :Semantics Satisfiability and validity

More information

Language of Propositional Logic

Language of Propositional Logic Logic A logic has: 1. An alphabet that contains all the symbols of the language of the logic. 2. A syntax giving the rules that define the well formed expressions of the language of the logic (often called

More information

CSCI 1010 Models of Computa3on. Lecture 02 Func3ons and Circuits

CSCI 1010 Models of Computa3on. Lecture 02 Func3ons and Circuits CSCI 1010 Models of Computa3on Lecture 02 Func3ons and Circuits Overview Func3ons and languages Designing circuits from func3ons Minterms and the DNF Maxterms and CNF Circuit complexity Algebra of Boolean

More information

Propositional Logic Basics Propositional Equivalences Normal forms Boolean functions and digital circuits. Propositional Logic.

Propositional Logic Basics Propositional Equivalences Normal forms Boolean functions and digital circuits. Propositional Logic. Propositional Logic Winter 2012 Propositional Logic: Section 1.1 Proposition A proposition is a declarative sentence that is either true or false. Which ones of the following sentences are propositions?

More information

CSC Discrete Math I, Spring Propositional Logic

CSC Discrete Math I, Spring Propositional Logic CSC 125 - Discrete Math I, Spring 2017 Propositional Logic Propositions A proposition is a declarative sentence that is either true or false Propositional Variables A propositional variable (p, q, r, s,...)

More information

PHIL12A Section answers, 16 February 2011

PHIL12A Section answers, 16 February 2011 PHIL12A Section answers, 16 February 2011 Julian Jonker 1 How much do you know? 1. Show that the following sentences are equivalent. (a) (Ex 4.16) A B A and A B A B (A B) A A B T T T T T T T T T T T F

More information

Sec$on Summary. Tautologies, Contradictions, and Contingencies. Logical Equivalence. Normal Forms (optional, covered in exercises in text)

Sec$on Summary. Tautologies, Contradictions, and Contingencies. Logical Equivalence. Normal Forms (optional, covered in exercises in text) Section 1.3 1 Sec$on Summary Tautologies, Contradictions, and Contingencies. Logical Equivalence Important Logical Equivalences Showing Logical Equivalence Normal Forms (optional, covered in exercises

More information

Announcements. CS243: Discrete Structures. Propositional Logic II. Review. Operator Precedence. Operator Precedence, cont. Operator Precedence Example

Announcements. CS243: Discrete Structures. Propositional Logic II. Review. Operator Precedence. Operator Precedence, cont. Operator Precedence Example Announcements CS243: Discrete Structures Propositional Logic II Işıl Dillig First homework assignment out today! Due in one week, i.e., before lecture next Tuesday 09/11 Weilin s Tuesday office hours are

More information

Section 1.2 Propositional Equivalences. A tautology is a proposition which is always true. A contradiction is a proposition which is always false.

Section 1.2 Propositional Equivalences. A tautology is a proposition which is always true. A contradiction is a proposition which is always false. Section 1.2 Propositional Equivalences A tautology is a proposition which is always true. Classic Example: P P A contradiction is a proposition which is always false. Classic Example: P P A contingency

More information

PHIL12A Section answers, 14 February 2011

PHIL12A Section answers, 14 February 2011 PHIL12A Section answers, 14 February 2011 Julian Jonker 1 How much do you know? 1. You should understand why a truth table is constructed the way it is: why are the truth values listed in the order they

More information

Sec$on Summary. Propositions Connectives. Truth Tables. Negation Conjunction Disjunction Implication; contrapositive, inverse, converse Biconditional

Sec$on Summary. Propositions Connectives. Truth Tables. Negation Conjunction Disjunction Implication; contrapositive, inverse, converse Biconditional Section 1.1 Sec$on Summary Propositions Connectives Negation Conjunction Disjunction Implication; contrapositive, inverse, converse Biconditional ruth ables 2 Proposi$ons A proposition is a declarative

More information

INTRODUCTION TO LOGIC. Propositional Logic. Examples of syntactic claims

INTRODUCTION TO LOGIC. Propositional Logic. Examples of syntactic claims Introduction INTRODUCTION TO LOGIC 2 Syntax and Semantics of Propositional Logic Volker Halbach In what follows I look at some formal languages that are much simpler than English and define validity of

More information

Introduc)on to Ar)ficial Intelligence

Introduc)on to Ar)ficial Intelligence Introduc)on to Ar)ficial Intelligence Lecture 9 Logical reasoning CS/CNS/EE 154 Andreas Krause First order logic (FOL)! Proposi)onal logic is about simple facts! There is a breeze at loca)on [1,2]! First

More information

Final Exam Theory Quiz Answer Page

Final Exam Theory Quiz Answer Page Philosophy 120 Introduction to Logic Final Exam Theory Quiz Answer Page 1. (a) is a wff (and a sentence); its outer parentheses have been omitted, which is permissible. (b) is also a wff; the variable

More information

2/18/14. What is logic? Proposi0onal Logic. Logic? Propositional Logic, Truth Tables, and Predicate Logic (Rosen, Sections 1.1, 1.2, 1.

2/18/14. What is logic? Proposi0onal Logic. Logic? Propositional Logic, Truth Tables, and Predicate Logic (Rosen, Sections 1.1, 1.2, 1. Logic? Propositional Logic, Truth Tables, and Predicate Logic (Rosen, Sections 1.1, 1.2, 1.3) TOPICS Propositional Logic Logical Operations Equivalences Predicate Logic CS160 - Spring Semester 2014 2 What

More information

2.2: Logical Equivalence: The Laws of Logic

2.2: Logical Equivalence: The Laws of Logic Example (2.7) For primitive statement p and q, construct a truth table for each of the following compound statements. a) p q b) p q Here we see that the corresponding truth tables for two statement p q

More information

Lecture 2. Logic Compound Statements Conditional Statements Valid & Invalid Arguments Digital Logic Circuits. Reading (Epp s textbook)

Lecture 2. Logic Compound Statements Conditional Statements Valid & Invalid Arguments Digital Logic Circuits. Reading (Epp s textbook) Lecture 2 Logic Compound Statements Conditional Statements Valid & Invalid Arguments Digital Logic Circuits Reading (Epp s textbook) 2.1-2.4 1 Logic Logic is a system based on statements. A statement (or

More information

Logic Part I: Classical Logic and Its Semantics

Logic Part I: Classical Logic and Its Semantics Logic Part I: Classical Logic and Its Semantics Max Schäfer Formosan Summer School on Logic, Language, and Computation 2007 July 2, 2007 1 / 51 Principles of Classical Logic classical logic seeks to model

More information

Solutions to Homework I (1.1)

Solutions to Homework I (1.1) Solutions to Homework I (1.1) Problem 1 Determine whether each of these compound propositions is satisable. a) (p q) ( p q) ( p q) b) (p q) (p q) ( p q) ( p q) c) (p q) ( p q) (a) p q p q p q p q p q (p

More information

ECE473 Lecture 15: Propositional Logic

ECE473 Lecture 15: Propositional Logic ECE473 Lecture 15: Propositional Logic Jeffrey Mark Siskind School of Electrical and Computer Engineering Spring 2018 Siskind (Purdue ECE) ECE473 Lecture 15: Propositional Logic Spring 2018 1 / 23 What

More information

CS250: Discrete Math for Computer Science. L6: CNF and Natural Deduction for PropCalc

CS250: Discrete Math for Computer Science. L6: CNF and Natural Deduction for PropCalc CS250: Discrete Math for Computer Science L6: CNF and Natural Deduction for PropCalc How to Simplify a PropCalc Formula: (p q) ((q r) p) How to Simplify a PropCalc Formula: 1. Get rid of s using def. of

More information

CSE 20: Discrete Mathematics

CSE 20: Discrete Mathematics Spring 2018 Summary Last time: Today: Logical connectives: not, and, or, implies Using Turth Tables to define logical connectives Logical equivalences, tautologies Some applications Proofs in propositional

More information

Part 1: Propositional Logic

Part 1: Propositional Logic Part 1: Propositional Logic Literature (also for first-order logic) Schöning: Logik für Informatiker, Spektrum Fitting: First-Order Logic and Automated Theorem Proving, Springer 1 Last time 1.1 Syntax

More information

Tautologies, Contradictions, and Contingencies

Tautologies, Contradictions, and Contingencies Section 1.3 Tautologies, Contradictions, and Contingencies A tautology is a proposition which is always true. Example: p p A contradiction is a proposition which is always false. Example: p p A contingency

More information

2. The Logic of Compound Statements Summary. Aaron Tan August 2017

2. The Logic of Compound Statements Summary. Aaron Tan August 2017 2. The Logic of Compound Statements Summary Aaron Tan 21 25 August 2017 1 2. The Logic of Compound Statements 2.1 Logical Form and Logical Equivalence Statements; Compound Statements; Statement Form (Propositional

More information

Logic: Propositional Logic (Part I)

Logic: Propositional Logic (Part I) Logic: Propositional Logic (Part I) Alessandro Artale Free University of Bozen-Bolzano Faculty of Computer Science http://www.inf.unibz.it/ artale Descrete Mathematics and Logic BSc course Thanks to Prof.

More information

AI Principles, Semester 2, Week 2, Lecture 5 Propositional Logic and Predicate Logic

AI Principles, Semester 2, Week 2, Lecture 5 Propositional Logic and Predicate Logic AI Principles, Semester 2, Week 2, Lecture 5 Propositional Logic and Predicate Logic Propositional logic Logical connectives Rules for wffs Truth tables for the connectives Using Truth Tables to evaluate

More information

CS 173 Lecture 2: Propositional Logic

CS 173 Lecture 2: Propositional Logic CS 173 Lecture 2: Propositional Logic José Meseguer University of Illinois at Urbana-Champaign 1 Propositional Formulas A proposition is a statement that is either true, T or false, F. A proposition usually

More information

1.3 Propositional Equivalences

1.3 Propositional Equivalences 1 1.3 Propositional Equivalences The replacement of a statement with another statement with the same truth is an important step often used in Mathematical arguments. Due to this methods that produce propositions

More information

Normal Forms of Propositional Logic

Normal Forms of Propositional Logic Normal Forms of Propositional Logic Bow-Yaw Wang Institute of Information Science Academia Sinica, Taiwan September 12, 2017 Bow-Yaw Wang (Academia Sinica) Normal Forms of Propositional Logic September

More information

HW1 graded review form? HW2 released CSE 20 DISCRETE MATH. Fall

HW1 graded review form? HW2 released CSE 20 DISCRETE MATH. Fall CSE 20 HW1 graded review form? HW2 released DISCRETE MATH Fall 2017 http://cseweb.ucsd.edu/classes/fa17/cse20-ab/ Today's learning goals Translate sentences from English to propositional logic using appropriate

More information

Math.3336: Discrete Mathematics. Propositional Equivalences

Math.3336: Discrete Mathematics. Propositional Equivalences Math.3336: Discrete Mathematics Propositional Equivalences Instructor: Dr. Blerina Xhabli Department of Mathematics, University of Houston https://www.math.uh.edu/ blerina Email: blerina@math.uh.edu Fall

More information

Logic and Inferences

Logic and Inferences Artificial Intelligence Logic and Inferences Readings: Chapter 7 of Russell & Norvig. Artificial Intelligence p.1/34 Components of Propositional Logic Logic constants: True (1), and False (0) Propositional

More information

~ p is always false. Based on the basic truth table for disjunction, if q is true then p ~

~ p is always false. Based on the basic truth table for disjunction, if q is true then p ~ MAT 101 Solutions Exam 2 (Logic, Part I) Multiple-Choice Questions 1. D Because this sentence contains exactly ten words, it is stating that it is false. But if it is taken to be false, then it has to

More information

Topic 1: Propositional logic

Topic 1: Propositional logic Topic 1: Propositional logic Guy McCusker 1 1 University of Bath Logic! This lecture is about the simplest kind of mathematical logic: propositional calculus. We discuss propositions, which are statements

More information

Logic: First Order Logic

Logic: First Order Logic Logic: First Order Logic Raffaella Bernardi bernardi@inf.unibz.it P.zza Domenicani 3, Room 2.28 Faculty of Computer Science, Free University of Bolzano-Bozen http://www.inf.unibz.it/~bernardi/courses/logic06

More information

Description Logics. Foundations of Propositional Logic. franconi. Enrico Franconi

Description Logics. Foundations of Propositional Logic.   franconi. Enrico Franconi (1/27) Description Logics Foundations of Propositional Logic Enrico Franconi franconi@cs.man.ac.uk http://www.cs.man.ac.uk/ franconi Department of Computer Science, University of Manchester (2/27) Knowledge

More information

CS156: The Calculus of Computation

CS156: The Calculus of Computation CS156: The Calculus of Computation Zohar Manna Winter 2010 It is reasonable to hope that the relationship between computation and mathematical logic will be as fruitful in the next century as that between

More information

CS 730/730W/830: Intro AI

CS 730/730W/830: Intro AI CS 730/730W/830: Intro AI 1 handout: slides 730W journal entries were due Wheeler Ruml (UNH) Lecture 9, CS 730 1 / 16 Logic First-Order Logic The Joy of Power Wheeler Ruml (UNH) Lecture 9, CS 730 2 / 16

More information

Automated Program Verification and Testing 15414/15614 Fall 2016 Lecture 2: Propositional Logic

Automated Program Verification and Testing 15414/15614 Fall 2016 Lecture 2: Propositional Logic Automated Program Verification and Testing 15414/15614 Fall 2016 Lecture 2: Propositional Logic Matt Fredrikson mfredrik@cs.cmu.edu October 17, 2016 Matt Fredrikson Propositional Logic 1 / 33 Propositional

More information

The task is to identify whether or not an arbitrary 3-CNF form is satisfiable. 3-DNF is used here for notational convenience.

The task is to identify whether or not an arbitrary 3-CNF form is satisfiable. 3-DNF is used here for notational convenience. EXPLORING BOUNDARY LOGIC 3SAT ALGORITHMS William Bricken February 1998 What follows is an exploration of P=NP. APPROACH The task is to identify whether or not an arbitrary 3-CNF form is satisfiable. 3-DNF

More information

CSE 20 DISCRETE MATH WINTER

CSE 20 DISCRETE MATH WINTER CSE 20 DISCRETE MATH WINTER 2017 http://cseweb.ucsd.edu/classes/wi17/cse20-ab/ Reminders Homework 3 due Sunday at noon Exam 1 in one week One note card can be used. Bring photo ID. Review sessions Thursday

More information

Propositional Logic: Part II - Syntax & Proofs 0-0

Propositional Logic: Part II - Syntax & Proofs 0-0 Propositional Logic: Part II - Syntax & Proofs 0-0 Outline Syntax of Propositional Formulas Motivating Proofs Syntactic Entailment and Proofs Proof Rules for Natural Deduction Axioms, theories and theorems

More information

Section 1.1: Logical Form and Logical Equivalence

Section 1.1: Logical Form and Logical Equivalence Section 1.1: Logical Form and Logical Equivalence An argument is a sequence of statements aimed at demonstrating the truth of an assertion. The assertion at the end of an argument is called the conclusion,

More information

Introduction to Decision Sciences Lecture 2

Introduction to Decision Sciences Lecture 2 Introduction to Decision Sciences Lecture 2 Andrew Nobel August 24, 2017 Compound Proposition A compound proposition is a combination of propositions using the basic operations. For example (p q) ( p)

More information

Computation and Logic Definitions

Computation and Logic Definitions Computation and Logic Definitions True and False Also called Boolean truth values, True and False represent the two values or states an atom can assume. We can use any two distinct objects to represent

More information

Compound Propositions

Compound Propositions Discrete Structures Compound Propositions Producing new propositions from existing propositions. Logical Operators or Connectives 1. Not 2. And 3. Or 4. Exclusive or 5. Implication 6. Biconditional Truth

More information

Logik für Informatiker Logic for computer scientists

Logik für Informatiker Logic for computer scientists Logik für Informatiker Logic for computer scientists Till Mossakowski WiSe 2013/14 Till Mossakowski Logic 1/ 24 Till Mossakowski Logic 2/ 24 Logical consequence 1 Q is a logical consequence of P 1,, P

More information

Unary negation: T F F T

Unary negation: T F F T Unary negation: ϕ 1 ϕ 1 T F F T Binary (inclusive) or: ϕ 1 ϕ 2 (ϕ 1 ϕ 2 ) T T T T F T F T T F F F Binary (exclusive) or: ϕ 1 ϕ 2 (ϕ 1 ϕ 2 ) T T F T F T F T T F F F Classical (material) conditional: ϕ 1

More information

Sample Problems for all sections of CMSC250, Midterm 1 Fall 2014

Sample Problems for all sections of CMSC250, Midterm 1 Fall 2014 Sample Problems for all sections of CMSC250, Midterm 1 Fall 2014 1. Translate each of the following English sentences into formal statements using the logical operators (,,,,, and ). You may also use mathematical

More information

Example. Logic. Logical Statements. Outline of logic topics. Logical Connectives. Logical Connectives

Example. Logic. Logical Statements. Outline of logic topics. Logical Connectives. Logical Connectives Logic Logic is study of abstract reasoning, specifically, concerned with whether reasoning is correct. Logic focuses on relationship among statements as opposed to the content of any particular statement.

More information

Introduction to Sets and Logic (MATH 1190)

Introduction to Sets and Logic (MATH 1190) Introduction to Sets Logic () Instructor: Email: shenlili@yorku.ca Department of Mathematics Statistics York University Sept 18, 2014 Outline 1 2 Tautologies Definition A tautology is a compound proposition

More information

Logik für Informatiker Proofs in propositional logic

Logik für Informatiker Proofs in propositional logic Logik für Informatiker Proofs in propositional logic WiSe 009/10 al consequence Q is a logical consequence of P 1,, P n, if all worlds that make P 1,, P n true also make Q true Q is a tautological consequence

More information

Propositional Logic: Equivalence

Propositional Logic: Equivalence Propositional Logic: Equivalence Alice Gao Lecture 5 Based on work by J. Buss, L. Kari, A. Lubiw, B. Bonakdarpour, D. Maftuleac, C. Roberts, R. Trefler, and P. Van Beek 1/42 Outline Propositional Logic:

More information

CSE 20 DISCRETE MATH WINTER

CSE 20 DISCRETE MATH WINTER CSE 20 DISCRETE MATH WINTER 2016 http://cseweb.ucsd.edu/classes/wi16/cse20-ab/ Reminders Exam 1 in one week One note sheet ok Review sessions Saturday / Sunday Assigned seats: seat map on Piazza shortly

More information

Logic, Sets, and Proofs

Logic, Sets, and Proofs Logic, Sets, and Proofs David A. Cox and Catherine C. McGeoch Amherst College 1 Logic Logical Operators. A logical statement is a mathematical statement that can be assigned a value either true or false.

More information

Propositional Logic Language

Propositional Logic Language Propositional Logic Language A logic consists of: an alphabet A, a language L, i.e., a set of formulas, and a binary relation = between a set of formulas and a formula. An alphabet A consists of a finite

More information

Conjunction: p q is true if both p, q are true, and false if at least one of p, q is false. The truth table for conjunction is as follows.

Conjunction: p q is true if both p, q are true, and false if at least one of p, q is false. The truth table for conjunction is as follows. Chapter 1 Logic 1.1 Introduction and Definitions Definitions. A sentence (statement, proposition) is an utterance (that is, a string of characters) which is either true (T) or false (F). A predicate is

More information

Logic and Discrete Mathematics. Section 3.5 Propositional logical equivalence Negation of propositional formulae

Logic and Discrete Mathematics. Section 3.5 Propositional logical equivalence Negation of propositional formulae Logic and Discrete Mathematics Section 3.5 Propositional logical equivalence Negation of propositional formulae Slides version: January 2015 Logical equivalence of propositional formulae Propositional

More information

3/29/2017. Logic. Propositions and logical operations. Main concepts: propositions truth values propositional variables logical operations

3/29/2017. Logic. Propositions and logical operations. Main concepts: propositions truth values propositional variables logical operations Logic Propositions and logical operations Main concepts: propositions truth values propositional variables logical operations 1 Propositions and logical operations A proposition is the most basic element

More information

Propositional Logic. Spring Propositional Logic Spring / 32

Propositional Logic. Spring Propositional Logic Spring / 32 Propositional Logic Spring 2016 Propositional Logic Spring 2016 1 / 32 Introduction Learning Outcomes for this Presentation Learning Outcomes... At the conclusion of this session, we will Define the elements

More information

More Propositional Logic Algebra: Expressive Completeness and Completeness of Equivalences. Computability and Logic

More Propositional Logic Algebra: Expressive Completeness and Completeness of Equivalences. Computability and Logic More Propositional Logic Algebra: Expressive Completeness and Completeness of Equivalences Computability and Logic Equivalences Involving Conditionals Some Important Equivalences Involving Conditionals

More information

Proofs Sec*ons 1.6, 1.7 and 1.8 of Rosen

Proofs Sec*ons 1.6, 1.7 and 1.8 of Rosen Proofs Sec*ons 1.6, 1.7 and 1.8 of Rosen Spring 2013 CSCE 235 Introduc5on to Discrete Structures Course web- page: cse.unl.edu/~cse235 Ques5ons: Piazza Outline Mo5va5on Terminology Rules of inference:

More information

Discrete Structures & Algorithms. Propositional Logic EECE 320 // UBC

Discrete Structures & Algorithms. Propositional Logic EECE 320 // UBC Discrete Structures & Algorithms Propositional Logic EECE 320 // UBC 1 Review of last lecture Pancake sorting A problem with many applications Bracketing (bounding a function) Proving bounds for pancake

More information

Mat 243 Exam 1 Review

Mat 243 Exam 1 Review OBJECTIVES (Review problems: on next page) 1.1 Distinguish between propositions and non-propositions. Know the truth tables (i.e., the definitions) of the logical operators,,,, and Write truth tables for

More information

02 Propositional Logic

02 Propositional Logic SE 2F03 Fall 2005 02 Propositional Logic Instructor: W. M. Farmer Revised: 25 September 2005 1 What is Propositional Logic? Propositional logic is the study of the truth or falsehood of propositions or

More information

PHIL12A Section answers, 28 Feb 2011

PHIL12A Section answers, 28 Feb 2011 PHIL12A Section answers, 28 Feb 2011 Julian Jonker 1 How much do you know? Give formal proofs for the following arguments. 1. (Ex 6.18) 1 A B 2 A B 1 A B 2 A 3 A B Elim: 2 4 B 5 B 6 Intro: 4,5 7 B Intro:

More information

CS 512, Spring 2017, Handout 10 Propositional Logic: Conjunctive Normal Forms, Disjunctive Normal Forms, Horn Formulas, and other special forms

CS 512, Spring 2017, Handout 10 Propositional Logic: Conjunctive Normal Forms, Disjunctive Normal Forms, Horn Formulas, and other special forms CS 512, Spring 2017, Handout 10 Propositional Logic: Conjunctive Normal Forms, Disjunctive Normal Forms, Horn Formulas, and other special forms Assaf Kfoury 5 February 2017 Assaf Kfoury, CS 512, Spring

More information

If f = ABC + ABC + A B C then f = AB C + A BC + AB C + A BC + A B C

If f = ABC + ABC + A B C then f = AB C + A BC + AB C + A BC + A B C Examples: If f 5 = AB + AB then f 5 = A B + A B = f 10 If f = ABC + ABC + A B C then f = AB C + A BC + AB C + A BC + A B C In terms of a truth table, if f is the sum (OR) of all the minterms with a 1 in

More information

Propositional Logic: Models and Proofs

Propositional Logic: Models and Proofs Propositional Logic: Models and Proofs C. R. Ramakrishnan CSE 505 1 Syntax 2 Model Theory 3 Proof Theory and Resolution Compiled at 11:51 on 2016/11/02 Computing with Logic Propositional Logic CSE 505

More information

1 Propositional Logic

1 Propositional Logic CS 2800, Logic and Computation Propositional Logic Lectures Pete Manolios Version: 384 Spring 2011 1 Propositional Logic The study of logic was initiated by the ancient Greeks, who were concerned with

More information

COMP219: Artificial Intelligence. Lecture 20: Propositional Reasoning

COMP219: Artificial Intelligence. Lecture 20: Propositional Reasoning COMP219: Artificial Intelligence Lecture 20: Propositional Reasoning 1 Overview Last time Logic for KR in general; Propositional Logic; Natural Deduction Today Entailment, satisfiability and validity Normal

More information

PUZZLE. You meet A, B, and C in the land of knights and knaves. A says Either B and I are both knights or we are both knaves.

PUZZLE. You meet A, B, and C in the land of knights and knaves. A says Either B and I are both knights or we are both knaves. PUZZLE You meet A, B, and C in the land of knights and knaves. A says Either B and I are both knights or we are both knaves. B says C and I are the same type. C says Either A is a knave or B is a knave.

More information

A Statement; Logical Operations

A Statement; Logical Operations A Statement; Logical Operations Mathematical logic is a branch of mathematics that deals with the formal principles, methods and criteria of validity of reasoning and knowledge. Logic is concerned with

More information

Chapter 4: Classical Propositional Semantics

Chapter 4: Classical Propositional Semantics Chapter 4: Classical Propositional Semantics Language : L {,,, }. Classical Semantics assumptions: TWO VALUES: there are only two logical values: truth (T) and false (F), and EXTENSIONALITY: the logical

More information

Logic and Proofs. (A brief summary)

Logic and Proofs. (A brief summary) Logic and Proofs (A brief summary) Why Study Logic: To learn to prove claims/statements rigorously To be able to judge better the soundness and consistency of (others ) arguments To gain the foundations

More information

Chapter 1, Section 1.1 Propositional Logic

Chapter 1, Section 1.1 Propositional Logic Discrete Structures Chapter 1, Section 1.1 Propositional Logic These class notes are based on material from our textbook, Discrete Mathematics and Its Applications, 6 th ed., by Kenneth H. Rosen, published

More information

Discrete Structures of Computer Science Propositional Logic III Rules of Inference

Discrete Structures of Computer Science Propositional Logic III Rules of Inference Discrete Structures of Computer Science Propositional Logic III Rules of Inference Gazihan Alankuş (Based on original slides by Brahim Hnich) July 30, 2012 1 Previous Lecture 2 Summary of Laws of Logic

More information

Introduction to Artificial Intelligence Propositional Logic & SAT Solving. UIUC CS 440 / ECE 448 Professor: Eyal Amir Spring Semester 2010

Introduction to Artificial Intelligence Propositional Logic & SAT Solving. UIUC CS 440 / ECE 448 Professor: Eyal Amir Spring Semester 2010 Introduction to Artificial Intelligence Propositional Logic & SAT Solving UIUC CS 440 / ECE 448 Professor: Eyal Amir Spring Semester 2010 Today Representation in Propositional Logic Semantics & Deduction

More information

Formal Verification Methods 1: Propositional Logic

Formal Verification Methods 1: Propositional Logic Formal Verification Methods 1: Propositional Logic John Harrison Intel Corporation Course overview Propositional logic A resurgence of interest Logic and circuits Normal forms The Davis-Putnam procedure

More information

https://vu5.sfc.keio.ac.jp/slide/

https://vu5.sfc.keio.ac.jp/slide/ 1 FUNDAMENTALS OF LOGIC NO.3 NORMAL FORMS Tatsuya Hagino hagino@sfc.keio.ac.jp lecture URL https://vu5.sfc.keio.ac.jp/slide/ 2 So Far What is Logic? mathematical logic symbolic logic Proposition A statement

More information

Numbers that are divisible by 2 are even. The above statement could also be written in other logically equivalent ways, such as:

Numbers that are divisible by 2 are even. The above statement could also be written in other logically equivalent ways, such as: 3.4 THE CONDITIONAL & BICONDITIONAL Definition. Any statement that can be put in the form If p, then q, where p and q are basic statements, is called a conditional statement and is written symbolically

More information

CHAPTER 4 CLASSICAL PROPOSITIONAL SEMANTICS

CHAPTER 4 CLASSICAL PROPOSITIONAL SEMANTICS CHAPTER 4 CLASSICAL PROPOSITIONAL SEMANTICS 1 Language There are several propositional languages that are routinely called classical propositional logic languages. It is due to the functional dependency

More information

CS156: The Calculus of Computation Zohar Manna Autumn 2008

CS156: The Calculus of Computation Zohar Manna Autumn 2008 Page 3 of 52 Page 4 of 52 CS156: The Calculus of Computation Zohar Manna Autumn 2008 Lecturer: Zohar Manna (manna@cs.stanford.edu) Office Hours: MW 12:30-1:00 at Gates 481 TAs: Boyu Wang (wangboyu@stanford.edu)

More information