16-ValidEquiv

16-ValidEquiv - Discussion #16 Chapter 2, Section 2.4 1/12...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Discussion #16 Chapter 2, Section 2.4 1/12 Discussion #16 Validity & Equivalences Discussion #16 Chapter 2, Section 2.4 2/12 Topics Validity Tautologies with Interpretations Contradictions with Interpretations Logical Equivalences Involving Quantifiers Rectification Discussion #16 Chapter 2, Section 2.4 3/12 Validity An expression that is true for all interpretations is said to be valid . (A valid expression is also call a tautology.) An expression that is true for no interpretation is said to be contradictory . (A contradictory expression is also called a contradiction.) If A is valid, A is contradictory. (a tautology) (a contradiction) Examples: P(x, y) P(x, y) P(x, y) P(x, y) is valid P(x, y) P(x, y) is contradictory Discussion #16 Chapter 2, Section 2.4 4/12 Laws are Valid All laws are valid. de Morgans: (P(x) Q(y)) P(x) Q(y) Identity: P(x) T P(x) When we replace by , the resulting expression is true for all interpretations....
View Full Document

This note was uploaded on 03/02/2012 for the course C S 236 taught by Professor Michaelgoodrich during the Winter '12 term at BYU.

Page1 / 12

16-ValidEquiv - Discussion #16 Chapter 2, Section 2.4 1/12...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online