Elimination of Quantifiers
A technique in mathematical logic to remove quantifiers from formulas, preserving logical…
Elementary Equivalence in Logic and Mathematics
Elementary equivalence signifies that two structures share all the same first-order sentences.…
Effectively Decidable Theory
An effectively decidable theory is a formal system where an algorithm can…
Effectively Decidable Relations
An effectively decidable relation is one where a mechanical method can definitively…
Effectively Computable Functions
An effectively computable function is one that can be calculated by an…
Downward Löwenheim–Skolem Theorem
The downward Löwenheim–Skolem theorem states that if a theory has an infinite…
Double Negation Introduction
The principle of double negation introduction states that for any proposition P,…
Double Negation Elimination
Double negation elimination is a core principle in classical logic. It states…