Math › Logic formulae

Formulas of predicate, mostly FOL, logic that express common mathematical notions. Formulae are given loosely, avoring the succinct loose-math-system to the stricter, FOL system, that relies on predicates excessively. The canonical example of this is ∀x ∈ ℕ (math-loose) vs ∀x.P(x) (strict-FOL) with the predicate P standing for the property of "being a natural number".