| Syntax rules | |
|---|---|
| TFL | |
| Propositional variables | single uppercase letters (A-Z) |
| Not | not ¬ ~ ∼ - − |
| And | and ∧ ^ & . · * |
| Or | or ∨ |
| Implies | imp → ⇒ ⊃ -> > |
| Iff | iff ↔ ≡ <-> |
| Contradiction | bot ⊥ XX # |
| FOL | |
| Atomic sentences | predicates followed by names, or identities (Pa, Fcdc, a = d, etc.) |
| Predicates | single uppercase letters except A and E |
| Names | single lowercase letters (a-r) |
| Variables | single lowercase letters (s-z) |
| Forall | forall x ∀x Ax ⋀x |
| Exists | exists x ∃x Ex ⋁x |
| ML | |
| Box | box □ [] |
| Diamond | dia ♢ <> |