DOCSLIB.ORG

6.1 Logic Statements Or Propositions Negation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
6.1 Logic Statements Or Propositions Negation 6.1 Logic Logic is not only the foundation of mathematics, but also is important in numerous fields including law, medicine, and science. Although the study of logic originated in antiquity, it was rebuilt and formalized in the 19th and early 20th century. George Boole (Boolean algebra) introduced mathematical methods to logic in 1847 while Georg Cantor did theoretical work on sets and discovered that there are many different sizes of infinite sets. Statements or Propositions A proposition or statement is a declaration which is either true or false. Some examples: 2+2 = 5 is a statement because it is a false declaration. Orange juice contains vitamin C is a statement that is true. Open the door. This is not considered a statement since we cannot assign a true or false value to this sentence. It is a command, but not a statement or proposition. Negation The negation of a statement, p , is “not p” and is denoted by ┐ p Truth table: p ┐ p TF FT If p is true, then its negation is false. If p is false, then its negation is true. 1 Disjunction A disjunction is of the form p V q and is read p or q. Truth table for disjunction: p q p V q TT T TF T FT T FF F A disjunction is true in all cases except when both p and q are false. Conjunction A conjunction is only true when both p and q are true. Otherwise, a conjunction of two statements will be false: Truth table: p q p ∧ q TT T TF F FT F FF F Conditional statement To understand the logic behind the truth table for the conditional statement, consider the following statement. “If you get an A in the class, I will give you five bucks.” Let p = statement “ You get an A in the class” Let q = statement “ I will give you five bucks.” Now, if p is true (you got an A) and I give you the five bucks, the truth value of p q is true. The contract was satisfied and both parties fulfilled the agreement. Now, suppose p is true (you got the A) and q is false (you did not get the five bucks). You fulfilled your part of the bargain, but weren’t rewarded with the five bucks. So p q is false since the contract was broken by the other party. Now, suppose p is false. You did not get an A but received five bucks anyway. (q is true) No contract was broken. There was no obligation to receive 5 bucks, so truth value of p q cannot be false, so it must be true. Finally, if both p and q are false, the contract was not broken. You did not receive the A and you did not receive the 5 bucks. So p q is true in this case. 2 Truth table for conditional p q p q TT T TF F FT T FF T Variations of the conditional Converse: The converse of p q is q p Contrapositive: The contrapositive of p q is ┐q ┐p Examples Let p = you receive 90% Let q = you receive an A in the course p q ? If you receive 90%, then you will receive an A in the course. Converse: q p If you receive an A in the course, then you receive 90% Is the statement true? No. What about the student who receives a score greater than 90? That student receives an A but did not achieve a score of exactly 90%. 3 Example 2 State the contrapositive in an English sentence: Let p = you receive 90% Let q = you receive an A in the course p q ? If you receive 90%, then you will receive an A in the course ┐q ┐p If you don’t receive an A in the course, then you didn’t receive 90%. The contrapositive is true not only for these particular statements but for all statements , p and q. Logical equivalent statements Show that pq → is logically equivalent to ¬∨p q We will construct the truth tables for both sides and determine that the truth values for each statement are identical. The next slide shows that both statements are logically equivalent. The red columns are identical indicating the final truth values of each statement. 4 6.2 Sets This section will discuss the symbolism and concepts of set theory Set properties and set notation Definition of set: A set is any collection of objects specified in such a way that we can determine whether or not an object is or is not in the collection. Example 1. Set A is the set of all the letters in the alphabet. Notation: A = { a, b, c, d, e, …z) We use capital letters to represent sets. We list the elements of the set within braces. The three dots … indicate that the pattern continues. We can determine that an object is or is not in the collection. For example . e ∈ A stands for “e is an element of , or e belongs to set A” . This statement is true. The statement “ 3 ∈ A is false, since the number 3 is not an element of set A. The statement “ 3 A”is true. Null set Example. What are the real number solutions of the equation? 2 x +=10 Answer: There are no real number solutions of this equation since no real number squared added to one can ever equal 0. We represent the solution as the null set { } or Ø 1 Set builder notation Sometimes it is convenient to represent sets using what is called set-builder notation. For example, instead of representing the set A, letters in the alphabet by the roster method, we can use set builder notation: {x x is letter of the English alphabet} means the same as { a , b , c, d, e , …z} 2 Example two. { x l x = 9 } = {3 , -3} . This is read as the set of all such that the square of x equals 9. The solution set consists of the two numbers 3 and -3. Subsets A ⊂ B means A is a subset of B. A is a subset of A if every element of A is also contained in B. For example, the set of integers denoted by { …-3, -2, -1, 0, 1, 2, 3, …} is a subset of the set of real numbers. Formal definition of subset: A ⊂ B means if x ∈ A, the x ∈ B ∅ (null set )is a subset of every set. To verify this statement, let’s use the definition of subset. “ if x ∈ ∅ , then x is an element of A. But since the null set contains no elements, the statement x is an element of the null set is false. Hence, we have a conditional statement in which the premise is false. We know that p q is true if p is false. Since p is false, we conclude that the conditional statement is true. That is “ if x belongs to the null set, then x belongs to set A” is true, which implies that the null set must be a member of every set. Therefore, the null set is a subset of every set. Number of subsets List all the subsets of set A = {bird, cat, dog} For convenience, we will use the notation A = {b , c, d} to represent set A. Solution: ∅ is a subset of A. We also know that every set is a subset of itself so A = {b , c, d } is a subset of set A since every element of set A is contained within set A. How many two-element subsets are there? We have {b, c}, {b, d} , {c, d} How many one-element subsets? { b} , {c} and {d} . There is a total of 8 subsets of set A if you count all the listed subsets. 2 Set operations The union of two sets is the set of all elements formed by combining all the elements of set A and all the elements of set B into one set. The symbolism used is The Venn Diagram representing the union of A and B is the entire region shaded yellow. A ∪ B A BxxAorxB=∈{} ∈ Example of Union The union of the rational numbers with the set of irrational numbers is the set of real numbers. Rational numbers are those numbers that can be expressed as fractions, while irrational numbers are numbers that cannot be represented exactly as fractions, such as 2 Rational numbers a/b, ¾, 2/3 , 0.6 Irrational numbers such as square root of two, Pi , square root of 3 Real numbers: represented by shaded blue-green region Intersection of sets A and B The intersection of sets A and B is the set of elements that is common to both sets A and B. It is symbolized as A∩ B = { x l x A and x B } A B Represented by Venn Diagrams: Intersection 3 Complement of a set To understand the complement of a set, we must first define the universal set. The set of all elements under consideration is called the universal set. For example, when discussing numbers, the universal set may consist of the set of real numbers. All other types of numbers (integers, rational numbers, irrational numbers ) are subsets of the universal set of real numbers. Complement of set A: The complement of a set A is defined as the set of elements that are contained in U, the universal set, but not contained in set A. The symbolism for the complement of set A follows: A’ = { x U|x A} Venn Diagram for complement of set A Yellow region= all The complement of set A is elements in U that represented by the regions are neither in A or B.
Load more

Recommended publications
  • Dialetheists' Lies About the Liar
    PRINCIPIA 22(1): 59–85 (2018) doi: 10.5007/1808-1711.2018v22n1p59 Published by NEL — Epistemology and Logic Research Group, Federal University of Santa Catarina (UFSC), Brazil. DIALETHEISTS’LIES ABOUT THE LIAR JONAS R. BECKER ARENHART Departamento de Filosofia, Universidade Federal de Santa Catarina, BRAZIL [email protected] EDERSON SAFRA MELO Departamento de Filosofia, Universidade Federal do Maranhão, BRAZIL [email protected] Abstract. Liar-like paradoxes are typically arguments that, by using very intuitive resources of natural language, end up in contradiction. Consistent solutions to those paradoxes usually have difficulties either because they restrict the expressive power of the language, orelse because they fall prey to extended versions of the paradox. Dialetheists, like Graham Priest, propose that we should take the Liar at face value and accept the contradictory conclusion as true. A logical treatment of such contradictions is also put forward, with the Logic of Para- dox (LP), which should account for the manifestations of the Liar. In this paper we shall argue that such a formal approach, as advanced by Priest, is unsatisfactory. In order to make contradictions acceptable, Priest has to distinguish between two kinds of contradictions, in- ternal and external, corresponding, respectively, to the conclusions of the simple and of the extended Liar. Given that, we argue that while the natural interpretation of LP was intended to account for true and false sentences, dealing with internal contradictions, it lacks the re- sources to tame external contradictions. Also, the negation sign of LP is unable to represent internal contradictions adequately, precisely because of its allowance of sentences that may be true and false.
    [Show full text]
  • Chapter 18 Negation
    Chapter 18 Negation Jong-Bok Kim Kyung Hee University, Seoul Each language has a way to express (sentential) negation that reverses the truth value of a certain sentence, but employs language-particular expressions and gram- matical strategies. There are four main types of negatives in expressing sentential negation: the adverbial negative, the morphological negative, the negative auxil- iary verb, and the preverbal negative. This chapter discusses HPSG analyses for these four strategies in marking sentential negation. 1 Modes of expressing negation There are four main types of negative markers in expressing negation in lan- guages: the morphological negative, the negative auxiliary verb, the adverbial negative, and the clitic-like preverbal negative (see Dahl 1979; Payne 1985; Zanut- tini 2001; Dryer 2005).1 Each of these types is illustrated in the following: (1) a. Ali elmalar-i ser-me-di-;. (Turkish) Ali apples-ACC like-NEG-PST-3SG ‘Ali didn’t like apples.’ b. sensayng-nim-i o-ci anh-usi-ess-ta. (Korean) teacher-HON-NOM come-CONN NEG-HON-PST-DECL ‘The teacher didn’t come.’ c. Dominique (n’) écrivait pas de lettre. (French) Dominique NEG wrote NEG of letter ‘Dominique did not write a letter.’ 1The term negator or negative marker is a cover term for any linguistic expression functioning as sentential negation. Jong-Bok Kim. 2021. Negation. In Stefan Müller, Anne Abeillé, Robert D. Borsley & Jean- Pierre Koenig (eds.), Head-Driven Phrase Structure Grammar: The handbook. Prepublished version. Berlin: Language Science Press. [Pre- liminary page numbering] Jong-Bok Kim d. Gianni non legge articoli di sintassi. (Italian) Gianni NEG reads articles of syntax ‘Gianni doesn’t read syntax articles.’ As shown in (1a), languages like Turkish have typical examples of morphological negatives where negation is expressed by an inflectional category realized on the verb by affixation.
    [Show full text]
  • Truth-Bearers and Truth Value*
    Truth-Bearers and Truth Value* I. Introduction The purpose of this document is to explain the following concepts and the relationships between them: statements, propositions, and truth value. In what follows each of these will be discussed in turn. II. Language and Truth-Bearers A. Statements 1. Introduction For present purposes, we will define the term “statement” as follows. Statement: A meaningful declarative sentence.1 It is useful to make sure that the definition of “statement” is clearly understood. 2. Sentences in General To begin with, a statement is a kind of sentence. Obviously, not every string of words is a sentence. Consider: “John store.” Here we have two nouns with a period after them—there is no verb. Grammatically, this is not a sentence—it is just a collection of words with a dot after them. Consider: “If I went to the store.” This isn’t a sentence either. “I went to the store.” is a sentence. However, using the word “if” transforms this string of words into a mere clause that requires another clause to complete it. For example, the following is a sentence: “If I went to the store, I would buy milk.” This issue is not merely one of conforming to arbitrary rules. Remember, a grammatically correct sentence expresses a complete thought.2 The construction “If I went to the store.” does not do this. One wants to By Dr. Robert Tierney. This document is being used by Dr. Tierney for teaching purposes and is not intended for use or publication in any other manner. 1 More precisely, a statement is a meaningful declarative sentence-type.
    [Show full text]
  • A Symmetric Lambda-Calculus Corresponding to the Negation
    A Symmetric Lambda-Calculus Corresponding to the Negation-Free Bilateral Natural Deduction Tatsuya Abe Software Technology and Artificial Intelligence Research Laboratory, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba, 275-0016, Japan [email protected] Daisuke Kimura Department of Information Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba, 274-8510, Japan [email protected] Abstract Filinski constructed a symmetric lambda-calculus consisting of expressions and continuations which are symmetric, and functions which have duality. In his calculus, functions can be encoded to expressions and continuations using primitive operators. That is, the duality of functions is not derived in the calculus but adopted as a principle of the calculus. In this paper, we propose a simple symmetric lambda-calculus corresponding to the negation-free natural deduction based bilateralism in proof-theoretic semantics. In our calculus, continuation types are represented as not negations of formulae but formulae with negative polarity. Function types are represented as the implication and but-not connectives in intuitionistic and paraconsistent logics, respectively. Our calculus is not only simple but also powerful as it includes a call-value calculus corresponding to the call-by-value dual calculus invented by Wadler. We show that mutual transformations between expressions and continuations are definable in our calculus to justify the duality of functions. We also show that every typable function has dual types. Thus, the duality of function is derived from bilateralism. 2012 ACM Subject Classification Theory of computation → Logic; Theory of computation → Type theory Keywords and phrases symmetric lambda-calculus, formulae-as-types, duality, bilateralism, natural deduction, proof-theoretic semantics, but-not connective, continuation, call-by-value Acknowledgements The author thanks Yosuke Fukuda, Tasuku Hiraishi, Kentaro Kikuchi, and Takeshi Tsukada for the fruitful discussions, which clarified contributions of the present paper.
    [Show full text]
  • Journal of Linguistics Negation, 'Presupposition'
    Journal of Linguistics http://journals.cambridge.org/LIN Additional services for Journal of Linguistics: Email alerts: Click here Subscriptions: Click here Commercial reprints: Click here Terms of use : Click here Negation, ‘presupposition’ and the semantics/pragmatics distinction ROBYN CARSTON Journal of Linguistics / Volume 34 / Issue 02 / September 1998, pp 309 ­ 350 DOI: null, Published online: 08 September 2000 Link to this article: http://journals.cambridge.org/abstract_S0022226798007063 How to cite this article: ROBYN CARSTON (1998). Negation, ‘presupposition’ and the semantics/pragmatics distinction. Journal of Linguistics, 34, pp 309­350 Request Permissions : Click here Downloaded from http://journals.cambridge.org/LIN, IP address: 144.82.107.34 on 12 Oct 2012 J. Linguistics (), –. Printed in the United Kingdom # Cambridge University Press Negation, ‘presupposition’ and the semantics/pragmatics distinction1 ROBYN CARSTON Department of Phonetics and Linguistics, University College London (Received February ; revised April ) A cognitive pragmatic approach is taken to some long-standing problem cases of negation, the so-called presupposition denial cases. It is argued that a full account of the processes and levels of representation involved in their interpretation typically requires the sequential pragmatic derivation of two different propositions expressed. The first is one in which the presupposition is preserved and, following the rejection of this, the second involves the echoic (metalinguistic) use of material falling in the scope of the negation. The semantic base for these processes is the standard anti- presuppositionalist wide-scope negation. A different view, developed by Burton- Roberts (a, b), takes presupposition to be a semantic relation encoded in natural language and so argues for a negation operator that does not cancel presuppositions.
    [Show full text]
  • Rhetorical Analysis
    RHETORICAL ANALYSIS PURPOSE Almost every text makes an argument. Rhetorical analysis is the process of evaluating elements of a text and determining how those elements impact the success or failure of that argument. Often rhetorical analyses address written arguments, but visual, oral, or other kinds of “texts” can also be analyzed. RHETORICAL FEATURES – WHAT TO ANALYZE Asking the right questions about how a text is constructed will help you determine the focus of your rhetorical analysis. A good rhetorical analysis does not try to address every element of a text; discuss just those aspects with the greatest [positive or negative] impact on the text’s effectiveness. THE RHETORICAL SITUATION Remember that no text exists in a vacuum. The rhetorical situation of a text refers to the context in which it is written and read, the audience to whom it is directed, and the purpose of the writer. THE RHETORICAL APPEALS A writer makes many strategic decisions when attempting to persuade an audience. Considering the following rhetorical appeals will help you understand some of these strategies and their effect on an argument. Generally, writers should incorporate a variety of different rhetorical appeals rather than relying on only one kind. Ethos (appeal to the writer’s credibility) What is the writer’s purpose (to argue, explain, teach, defend, call to action, etc.)? Do you trust the writer? Why? Is the writer an authority on the subject? What credentials does the writer have? Does the writer address other viewpoints? How does the writer’s word choice or tone affect how you view the writer? Pathos (a ppeal to emotion or to an audience’s values or beliefs) Who is the target audience for the argument? How is the writer trying to make the audience feel (i.e., sad, happy, angry, guilty)? Is the writer making any assumptions about the background, knowledge, values, etc.
    [Show full text]
  • Expressing Negation
    Expressing Negation William A. Ladusaw University of California, Santa Cruz Introduction* My focus in this paper is the syntax-semantics interface for the interpretation of negation in languages which show negative concord, as illustrated in the sentences in (1)-(4). (1) Nobody said nothing to nobody. [NS English] ‘Nobody said anything to anyone.’ (2) Maria didn’t say nothing to nobody. [NS English] ‘Maria didn’t say anything to anyone.’ (3) Mario non ha parlato di niente con nessuno. [Italian] ‘Mario hasn’t spoken with anyone about anything.’ (4) No m’ha telefonat ningú. [Catalan] ‘Nobody has telephoned me.’ Negative concord (NC) is the indication at multiple points in a clause of the fact that the clause is to be interpreted as semantically negated. In a widely spoken and even more widely understood nonstandard dialect of English, sentences (1) and (2) are interpreted as synonymous with those given as glosses, which are also well-formed in the dialect. The examples in (3) from Italian and (4) from Catalan illustrate the same phenomenon. The occurrence in these sentences of two or three different words, any one of which when correctly positioned would be sufficient to negate a clause, does not guarantee that their interpretation involves two or three independent expressions of negation. These clauses express only one negation, which is, on one view, simply redundantly indicated in two or three different places; each of the italicized terms in these sentences might be seen as having an equal claim to the function of expressing negation. However closer inspection indicates that this is not the correct view.
    [Show full text]
  • Deduction (I) Tautologies, Contradictions And
    D (I) T, & L L October , Tautologies, contradictions and contingencies Consider the truth table of the following formula: p (p ∨ p) () If you look at the final column, you will notice that the truth value of the whole formula depends on the way a truth value is assigned to p: the whole formula is true if p is true and false if p is false. Contrast the truth table of (p ∨ p) in () with the truth table of (p ∨ ¬p) below: p ¬p (p ∨ ¬p) () If you look at the final column, you will notice that the truth value of the whole formula does not depend on the way a truth value is assigned to p. The formula is always true because of the meaning of the connectives. Finally, consider the truth table table of (p ∧ ¬p): p ¬p (p ∧ ¬p) () This time the formula is always false no matter what truth value p has. Tautology A statement is called a tautology if the final column in its truth table contains only ’s. Contradiction A statement is called a contradiction if the final column in its truth table contains only ’s. Contingency A statement is called a contingency or contingent if the final column in its truth table contains both ’s and ’s. Let’s consider some examples from the book. Can you figure out which of the following sentences are tautologies, which are contradictions and which contingencies? Hint: the answer is the same for all the formulas with a single row. () a. (p ∨ ¬p), (p → p), (p → (q → p)), ¬(p ∧ ¬p) b.
    [Show full text]
  • Sets, Propositional Logic, Predicates, and Quantifiers
    COMP 182 Algorithmic Thinking Sets, Propositional Logic, Luay Nakhleh Computer Science Predicates, and Quantifiers Rice University !1 Reading Material ❖ Chapter 1, Sections 1, 4, 5 ❖ Chapter 2, Sections 1, 2 !2 ❖ Mathematics is about statements that are either true or false. ❖ Such statements are called propositions. ❖ We use logic to describe them, and proof techniques to prove whether they are true or false. !3 Propositions ❖ 5>7 ❖ The square root of 2 is irrational. ❖ A graph is bipartite if and only if it doesn’t have a cycle of odd length. ❖ For n>1, the sum of the numbers 1,2,3,…,n is n2. !4 Propositions? ❖ E=mc2 ❖ The sun rises from the East every day. ❖ All species on Earth evolved from a common ancestor. ❖ God does not exist. ❖ Everyone eventually dies. !5 ❖ And some of you might already be wondering: “If I wanted to study mathematics, I would have majored in Math. I came here to study computer science.” !6 ❖ Computer Science is mathematics, but we almost exclusively focus on aspects of mathematics that relate to computation (that can be implemented in software and/or hardware). !7 ❖Logic is the language of computer science and, mathematics is the computer scientist’s most essential toolbox. !8 Examples of “CS-relevant” Math ❖ Algorithm A correctly solves problem P. ❖ Algorithm A has a worst-case running time of O(n3). ❖ Problem P has no solution. ❖ Using comparison between two elements as the basic operation, we cannot sort a list of n elements in less than O(n log n) time. ❖ Problem A is NP-Complete.
    [Show full text]
  • On Axiomatizations of General Many-Valued Propositional Calculi
    On axiomatizations of general many-valued propositional calculi Arto Salomaa Turku Centre for Computer Science Joukahaisenkatu 3{5 B, 20520 Turku, Finland asalomaa@utu.fi Abstract We present a general setup for many-valued propositional logics, and compare truth-table and axiomatic stipulations within this setup. Results are obtained concerning cases, where a finitary axiomatization is (resp. is not) possible. Related problems and examples are discussed. 1 Introduction Many-valued systems of logic are constructed by introducing one or more truth- values between truth and falsity. Truth-functions associated with the logical connectives then operate with more than two truth-values. For instance, the truth-function D associated with the 3-valued disjunction might be defined for the truth-values T;I;F (true, intermediate, false) by D(x; y) = max(x; y); where T > I > F: If the truth-function N associated with negation is defined by N(T ) = F; N(F ) = T;N(I) = I; the law of the excluded middle is not valid, provided \validity" means that the truth-value t results for all assignments of values for the variables. On the other hand, many-valuedness is not so obvious if the axiomatic method is used. As such, an ordinary axiomatization is not many-valued. Truth-tables are essential for the latter. However, in many cases it is possi- ble to axiomatize many-valued logics and, conversely, find many-valued models for axiom systems. In this paper, we will investigate (for propositional log- ics) interconnections between such \truth-value stipulations" and \axiomatic stipulations". A brief outline of the contents of this paper follows.
    [Show full text]
  • Mathematical Logic Part One
    Mathematical Logic Part One An Important Question How do we formalize the logic we've been using in our proofs? Where We're Going ● Propositional Logic (Today) ● Basic logical connectives. ● Truth tables. ● Logical equivalences. ● First-Order Logic (Today/Friday) ● Reasoning about properties of multiple objects. Propositional Logic A proposition is a statement that is, by itself, either true or false. Some Sample Propositions ● Puppies are cuter than kittens. ● Kittens are cuter than puppies. ● Usain Bolt can outrun everyone in this room. ● CS103 is useful for cocktail parties. ● This is the last entry on this list. More Propositions ● I came in like a wrecking ball. ● I am a champion. ● You're going to hear me roar. ● We all just entertainers. Things That Aren't Propositions CommandsCommands cannotcannot bebe truetrue oror false.false. Things That Aren't Propositions QuestionsQuestions cannotcannot bebe truetrue oror false.false. Things That Aren't Propositions TheThe firstfirst halfhalf isis aa validvalid proposition.proposition. I am the walrus, goo goo g'joob JibberishJibberish cannotcannot bebe truetrue oror false. false. Propositional Logic ● Propositional logic is a mathematical system for reasoning about propositions and how they relate to one another. ● Every statement in propositional logic consists of propositional variables combined via logical connectives. ● Each variable represents some proposition, such as “You liked it” or “You should have put a ring on it.” ● Connectives encode how propositions are related, such as “If you liked it, then you should have put a ring on it.” Propositional Variables ● Each proposition will be represented by a propositional variable. ● Propositional variables are usually represented as lower-case letters, such as p, q, r, s, etc.
    [Show full text]
  • 12 Propositional Logic
    CHAPTER 12 ✦ ✦ ✦ ✦ Propositional Logic In this chapter, we introduce propositional logic, an algebra whose original purpose, dating back to Aristotle, was to model reasoning. In more recent times, this algebra, like many algebras, has proved useful as a design tool. For example, Chapter 13 shows how propositional logic can be used in computer circuit design. A third use of logic is as a data model for programming languages and systems, such as the language Prolog. Many systems for reasoning by computer, including theorem provers, program verifiers, and applications in the field of artificial intelligence, have been implemented in logic-based programming languages. These languages generally use “predicate logic,” a more powerful form of logic that extends the capabilities of propositional logic. We shall meet predicate logic in Chapter 14. ✦ ✦ ✦ ✦ 12.1 What This Chapter Is About Section 12.2 gives an intuitive explanation of what propositional logic is, and why it is useful. The next section, 12,3, introduces an algebra for logical expressions with Boolean-valued operands and with logical operators such as AND, OR, and NOT that Boolean algebra operate on Boolean (true/false) values. This algebra is often called Boolean algebra after George Boole, the logician who first framed logic as an algebra. We then learn the following ideas. ✦ Truth tables are a useful way to represent the meaning of an expression in logic (Section 12.4). ✦ We can convert a truth table to a logical expression for the same logical function (Section 12.5). ✦ The Karnaugh map is a useful tabular technique for simplifying logical expres- sions (Section 12.6).
    [Show full text]