"the use of a fact table, is the sentence below a tautology, contradiction or contingency? (P => Q) <=> (urcorner P vee Q)

ajanlr 2022-10-15 Answered
the use of a fact table, is the sentence below a tautology, contradiction or contingency?
( P Q ) ( P Q )
Also, I am not sure what the double headed arrow is supposed to mean. I know a single headed arrow means "implies" but I am not sure about the double headed one.
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Answers (1)

Marlene Welch
Answered 2022-10-16 Author has 23 answers
If we setup a truth table:
P Q P Q ¬ P Q 0 0 1 1 0 1 1 1 1 0 0 0 1 1 1 1
P Q ¬ P Q ( P Q ) ( ¬ P Q ) 1 1 1 1 1 1 0 0 1 1 1 1
Your expression gives nothing but 1, so therefore it's a tautology.
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