Equivalent form of biconditional
48213
proving logical equivalence $(P \leftrightarrow Q) \equiv (P \wedge Q) \vee (\neg P \wedge \neg Q)$
83996
For any two sets $A,B$ , $|A|\leq|B|$ or $|B|\leq|A|$
37924
Equivalence of norms proof
32180
Why is "$A$ unless $B$" equivalent to $A \lor B$?
128866
Isomorphism between dual space and bilinear forms
62770
Does $a\mid bc$ imply $a\mid b$ or $a\mid c$?
87955
How to prove that $P \rightarrow Q$ is equivalent with $\neg P \lor Q $?
62817
Functions which are Continuous, but not Bicontinuous
28822
$|x| - |y| \leq |x-y|?$
62172
Why does $-b < a < b \iff |a| < b$?
150674
Uniqueness in existence of a bilinear form
23946
Prove the definitions of $e$ to be equivalent
63656
Ways to write 'P => Q'
157490
Statements equivalent to the Axiom of Choice
84999
$\exp(A)$ is orthogonal iff $A$ is skew symmetric
34045
3 Statements of axiom of choice are equivalent
87265
If $(A-\lambda{I})$ is $\lambda$-equivalent to $(B-\lambda{I})$ then $A$ is similar to $B$