Substitution Instance in Logic
A substitution instance is the result of replacing variables in a well-formed…
Structural Rule in Logic
A structural rule in logic, particularly proof theory, governs the manipulation of…
Strong Counterexample in Intuitionistic Logic
A strong counterexample in intuitionistic logic disproves an instance of the law…
Single Turnstile Symbol in Logic
The single turnstile (⊢) symbol in logic signifies syntactic entailment. It indicates…
Sequent Calculus: A Formal System for Logical Deduction
Sequent calculus is a formal system for logical entailments, representing deductions as…
Sequent Calculus: A Formal System for Logical Deduction
Sequent calculus is a formal system representing logical deductions. It uses sequences…
Rule of Replacement in Formal Logic
A fundamental principle in formal logic that permits substituting logically equivalent expressions…
Reverse Mathematics
Reverse mathematics investigates the logical strength of mathematical theorems. It aims to…