FOL Necessary Falsity Validity
95851
Validity of an argument with a contradictory conclusion
88281
Mixing and Distributing Qualifiers ($\forall x$, $\exists x$)
132701
Contradicting Fubini's theorem
32325
Can there be a valid argument which has a tautology as a conclusion?
49994
Deduction of $\forall y \exists x (x=y)$
6166
Is the following statement provable?
106799
Proof Verification: Converse of Intermediate Value Theorem
109858
How could a statement be true without proof?
43700
Are proofs by contradiction really logical?
8342
Is short-circuiting logical operators mandated? And evaluation order?
136584
Understanding connection between terms tautology, contradiction, contingent, satisfiable, unsatisfiable, valid and invalid
126633
Is a contradiction enough to prove a set equality to $\varnothing$?
86248
Is $\exists x(x=a)$ a valid formula in first order logic with equality?
6126
What is the difference between validity and satisfiability?
144396
fitch style proof problem regarding rule of inferences
67238
Requesting review of technically inaccurate answers
75600
Is Gödel's modified liar an illogical statement?