Determine if the statements are true. If they are true prove it, and if they are false, give a counterexample.
113695
Show that there is no integer n with $\phi(n)$ = 14
35370
Why is this proposition provable and its converse not?
122015
"This statement is false" - Propositional Logic
3663
Finding counterexamples in elementary set theory.
68880
propositional calculus problem, how to prove this right or wrong?
134120
Prove statement with a counter-example: For all sets S, T and V, V ∪ (S ∩ T) = (V ∪ S) ∩ T is false
157625
How to prove conditional in Coq?
121720
Given ∃x.¬p(x), use the Fitch System to prove ¬∀x.p(x).
15721
"Is it proved that ...?" vs. "Has it been proven that ...?"
135957
Why in an inconsistent axiom system every statement is true? (For Dummies)
10598
Contrapositive Fitch Proof
68607
Could an argument with false Premises and a true Conclusion be logically valid?
105303
'Obvious' theorems that are actually false
143627
Use the Fitch system to prove the tautology (p ∨ ¬p)
136577
In formal logic, how is it possible for an argument with a contradictory conclusion to be valid?
142026
Show that $A∩B∩C= ∅$ is only true when $A∩B = ∅, A∩C = ∅$ or $B∩C = ∅$ or show a counterexample.
112539
Can I disprove a claim using the contrapositive?