Proof by contradiction, status of initial assumption after the proof is complete.
43700
Are proofs by contradiction really logical?
147874
Why does the existence of independent statements not prove consistency?
144129
Is it okay to dispute the premise of a question?
4769
Any reasons why the basis case can't be at the end of a mathematical induction proof?
153532
Proving $a^2$ is even $\implies$ $a$ is even by contradiction
75600
Is Gödel's modified liar an illogical statement?
155897
Proof by induction - is this correct?
50804
It seems obvious, but how to prove it formally?
65895
Irrationality proofs not by contradiction
129185
Understanding the truth value for ⇏ when antecedent is false and consequent is true.
113344
How do we prove that something is unprovable?
95851
Validity of an argument with a contradictory conclusion
101710
What does it mean to prove statements or solve problems "from first principles"?
121605
A coin tossing game which leads to a contradiction
126633
Is a contradiction enough to prove a set equality to $\varnothing$?
31299
Using the Fitch system, how do I prove $((p \implies q) \implies p)\implies p$?
126870
Show that axiom of replacement implies from the Axiom of Specification [Proof Verification]