¬ - Answers NOT
(__negation__The statement ¬A is true if and only if A is false. A slash placed through another operator
is the same as "¬" placed in front. )
∧ - Answers AND
(__conjunction__The ampersand ( & ) or dot ( · ) are also often used.)
∨ - Answers OR
(__disjunction__ This is the inclusive disjunction, equivalent to and/or in English.)
⊕ - Answers exclusive disjunction (XOR)
(⊕ means that only one of the connected propositions is true, equivalent to either...or. Sometimes ⊻ is
used.)
| - Answers alternative denial (NAND)
(Means "not both". Sometimes written as ↑)
↓ - Answers joint denial (NOR)
(Means "neither/nor".)
→ - Answers if/then
(__conditional__Many logicians use the symbol ⊃ instead. This is also known as material implication.)
↔ - Answers biconditional (iff)
(Means "if and only if" ≡ is sometimes used, but this site reserves that symbol for equivalence.)
∀ - Answers universal quantifier
(Means "for all", so ∀xPx means that Px is true for every x.)
∃ - Answers existential quantifier
(Means "there exists", so ∃xPx means that Px is true for at least one x.)
⊨ - Answers implication
(α ⊨ β means that β follows from α)
≡ - Answers equivalence