How does one prove that proof by contradiction has completely and utterly failed?
17073
Using proof by contradiction vs proof of the contrapositive
153532
Proving $a^2$ is even $\implies$ $a$ is even by contradiction
56030
Could you prove the theorem?
75387
A proof that $1=2$. May I know why it’s false?
36503
Nicomachus theorem proof - what did I do wrong?
158335
Why is this $0 = 1$ proof wrong?
141814
Proofs using theorems instead of axioms
40048
Finding the fallacy in this broken proof
20190
Counter Proof to determinism?
48030
Axiom of Choice: Where does my argument for proving the axiom of choice fail? Help me understand why this is an axiom, and not a theorem.
87257
How to prove this sequent using natural deduction?
75529
Series prove or disprove statement
105303
'Obvious' theorems that are actually false
127733
How to prove De Morgan’s laws without using contradictions
89535
fake proof of $\forall a. \forall b. a = b \to 1 = 0$
83981
How to prove those "curious identities"?
2926
The contradiction method used to prove that the square root of a prime is irrational