How to typset $:\iff$ (logical equivalence)?
38092
Symbol for "defined to be logically equivalent" (:⇔)
25997
Conditions Equivalent to Injectivity
54719
How to handle equality constraints in this problem?
65910
Reflexivity of equivalence relations
129062
Distinguishing definitions from equivalences.
87928
Proof of logical equivalence of biconditional and other proposition
52179
What's a functional replacement for if-then statements?
64786
How can I linearize the IFF-THEN constraint with binary and continuous variable?
100844
How should I understand "$A$ unless $B$"?
62172
Why does $-b < a < b \iff |a| < b$?
123682
Can I use an "if" clause without "then"?
85437
Python's equivalent of && (logical-and) in an if-statement
68244
Is ∅ equivalent to {∅}?
5293
Show that the logic $ \ \forall x \exists y \ P(x,y) \ $ is not logically equivalent to $ \ \exists x \forall y \ P(x,y) \ $
109904
Test if two things typeset identical results
108528
How to compare functions?
157625
How to prove conditional in Coq?