Wiki-ch2

Additional Wiki pages for Chapter 2

Truth tables

Truth tables for connectives

AND (∧)

Symbol: ∧
Sentence: Harry is a student and Snape is a teacher.
Formulae: student(harry) ∧ teacher(snape)

Truthtable AND

OR (∨)

Symbol: ∨
Sentence: Harry is a student or Snape is a teacher.
Formulae: student(harry) ∨ teacher(snape)

Truthtable OR

IF/THEN (⊃, →)

Symbol: ⊃, → (Note: We use the symbol ⊃ in the textbook as it is more common in the logical literature.)
Sentence: If Harry is a student then Snape is a teacher.
Formula: student(harry) ⊃ teacher(snape)

Truthtable IF/THEN

NOT (¬)

Symbol: ¬
Sentence: Harry is not a student.
Formula: ¬student(harry)

The original formula has to be false for the overall statement to be true.

Example: Only if student(harry) is false, ¬student(harry) is true.

Truthtable NOT

Truth tables for complex formulae

Truth tables are also useful to compute the truth value of complex formulae. This is shown in the following podcast, created by User:Lisa Lisa Günthner.

<mediaplayer>http://www.youtube.com/watch?v=ZWdltj5Mqdc</mediaplayer>