propositional calculus problem, is this right proof?
68880
propositional calculus problem, how to prove this right or wrong?
3820
Prove that $||x|-|y||\le |x-y|$
15809
The problem of x = ln(x)
147528
Where's the error in this $2=1$ fake proof?
120600
Real analysis derivate problem. How can I prove this?
49453
Why do I have to solve for $x$ in this proof, if I choose not to find a counterexample?
104124
Prove or disprove: $A-(B-C) = (A-B)-C$
87928
Proof of logical equivalence of biconditional and other proposition
148790
Basic question about proofs with the goal $\exists x P(x)$
93410
How to prove ~ (~P & ~Q) : P ∨ Q by natural deduction
29629
Distinguishing between valid and fallacious arguments (propositional calculus)
75141
Quotient-Remainder Theorem Proving
40048
Finding the fallacy in this broken proof
77286
Proving set theory question
143248
What approach should I take to establish this logical proof?
39908
Finding the error in this proof that 1=2
126633
Is a contradiction enough to prove a set equality to $\varnothing$?