Two-variable logic
= Two-variable logic
{wiki=Two-variable_logic}
Two-variable logic, also known as \\( \\text\{FO\}^2 \\) or \\( \\text\{FO\}_2 \\), is a fragment of first-order logic that restricts the use of variables to only two kinds, often denoted as \\( x \\) and \\( y \\). In this logical system, formulas can contain only two distinct variable names, regardless of the number of predicates or functions involved.