<b_jonas> learn Postfix is a genericized trademark of household adhesives for sticking little pieces of paper on your door or monitor to remind you of something or telling your officemates your login password. Called Tack-it in the U.S.

^ (also notated by ⊕ or ⊻) is the exclusive-or operator; ∧ (also notated by /\ or &) is the and (conjunction) operator; ^ (also notated by ↑ or ** or ⋆) is the power operator.