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Metamath Proof Explorer


Theorem spi

Description: Inference rule of universal instantiation, or universal specialization. Converse of the inference rule of (universal) generalization ax-gen . Contrary to the rule of generalization, its closed form is valid, see sp . (Contributed by NM, 5-Aug-1993)

Ref Expression
Hypothesis spi.1 𝑥 𝜑
Assertion spi 𝜑

Proof

Step Hyp Ref Expression
1 spi.1 𝑥 𝜑
2 sp ( ∀ 𝑥 𝜑𝜑 )
3 1 2 ax-mp 𝜑