## 3.3 Outline

- Biconditional, implication, and logical equivalence
- definition of biconditional
- verifying tautologies
- implication
- equivalence

- Laws of logic
- law of double negation
- law of contraposition
- De Morgan’s laws

- Negation of a compound statement
- negation of a conditional
- language analysis

- Miscellaneous operators
- either
*p*or*q* - neither
*p*nor*q*

*p*unless*q**p*because*q*

- no
*p*is*q*

- either

## 3.3 Essential Ideas

The biconditional tests to see if two statements have the same truth values. The formal definition is given here:

Additional operators: