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Metamath Proof Explorer

Theorem negex

Description: A negative is a set. (Contributed by NM, 4-Apr-2005)

Ref Expression
Assertion negex ⊢ − A ∈ V

Proof

Step Hyp Ref Expression
1 df-neg ⊢ − A = 0 − A
2 1 ovexi ⊢ − A ∈ V