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Exercise 558Logic, sets and proofs › Quantifiers and negationL1Added 3 Nov 2026

Bounded quantifiers

#bounded quantifiers#notation#domain

Statement

Rewrite ∀x∈[0,1], f(x)≥0\forall x\in[0,1],\ f(x)\ge0 using an unbounded quantifier.

Hint

[0,1][0,1] is defined by a predicate on R\mathbb{R}.

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Solution

Bounded form. ∀x∈[0,1], f(x)≥0\forall x\in[0,1],\ f(x)\ge0.

Unbounded form. ∀x∈R, (0≤x≤1⇒f(x)≥0)\forall x\in\mathbb{R},\ (0\le x\le1\Rightarrow f(x)\ge0).

Conclusion. Bounded quantifiers are abbreviations for unbounded quantifiers with a membership predicate.