Example image of eyePlorer eyePlorer map for 'Sentence (mathematical logic)': Sentence Statement (logic) Free variables and bound variables Mathematical logic Predicate logic Well-formed formula Proposition Structure (mathematical logic) Truth value First-order logic Real number Square (algebra) Diagonal lemma Disjunction and existence properties Independence (mathematical logic) Lindenbaum–Tarski algebra Multiple-conclusion logic Theory (mathematical logic) Ω-consistent theory Atomic sentence Complete theory Bounded quantifier Tarski's axioms Algebraic logic Open sentence Boolean-valued function Gödel's incompleteness theorems True arithmetic Non-logical symbol Elementary class Interpretation (logic) Quantifier elimination Valuation (logic) Equivalence relation Syntax (logic) Infinitary logic Deduction theorem Object language Formal language Predicate functor logic Model theory Forcing (mathematics) List of algebraic structures