Linked from
The 75 pages that link to First-order logic, each with the reason it gives.
Higher-order logicCompared with: It provides the baseline that higher-order quantifiers extend.
Prenex normal formNarrower topic: Prenex form is a normal form for formulas in this logic.
Skolem normal formNarrower topic: Skolem normal form is defined for formulas in this logic.
Axiom of Empty SetRelated: The axiom is commonly expressed as a sentence in first-order logic.
Lindström's theoremBroader topic: It is the logic characterized by the theorem.