 Formal semantics

Formal semantics describes linguistic meaning with explicit mathematical representations and rules for combining them. A truth condition states when a declarative expression is true in a model; compositional semantics explains how meanings depend on both the parts and their arrangement. A syntactic category alone need not determine the semantic operation.^[ref]

In a toy model, let $B=\{1,2\}$ denote the boxes and $R=\{2,3\}$ the red objects. “Every box is red” is true exactly when $B\subseteq R$, which fails here. “Some box is red” is true when $B\cap R\ne \varnothing$, which holds. The difference comes from the quantifier's rule, not a change in the noun's denotation. Such finite examples make competing semantic proposals testable while leaving conversational interpretation to additional assumptions about context and pragmatics.