DM 2c PropositionalLogic
DM 2c PropositionalLogic
DM 2c PropositionalLogic
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Course Code: CSC 1204 Course Title: Discrete Mathematics
(e) p only if q
(f) q if p , or
q, if p
(g) q whenever p
(h) q when p
(i) q unless p
Remember!
Converse: p q ==> q p
Example: “If it is noon, then I am hungry.”
Converse: “If I am hungry, then it is noon.”
Contrapositive: p q ==> q p
Example: “If it is noon, then I am hungry.”
Contrapositive: “If I am not hungry, then it is not noon.”
Inverse: p q ==> p q
Example: “If it is noon, then I am hungry.”
Inverse: “If it is not noon, then I am not hungry.”
Bi-Conditional
• Let p and q be propositions.
• The bi-conditional statement p q is the proposition “p if
and only if q.”
• The bi-conditional statement p q is true when p and q
have the same truth values, and is false otherwise.
• Bi-conditional statements are also called “bi-implications”
Solution:
“You can take the flight if and only if you buy a ticket”
How to Construct a Truth Table for a
Compound Proposition?