Logic Symbols

Symbol	Meaning
$\exists$	There exists
$\forall$	For all
$p\to q$	p implies q (if p, then q)
$p\leftrightarrow q$	p if and only if q This is a connective, like $\wedge$
$p\iff q$	p if and only if q (p and q are equivalent) (This is the same as $\leftrightarrow$ ?)
$p\equiv q$	p is equivalent to q (equal, but for logic) This is a “fact”, like $\in$
$x\in A$	x is an element of A
$A\subseteq B$	A is a subset of B
$A-B$	Difference between set A and B
~p	NOT p (Negation)
$p\wedge q$	$p$ AND $q$
$p\vee q$	$p$ OR $q$
$A_0:=A$	Set $A_0$ to be a working copy of $A$ (not a logic symbol)