wnfOLD - Metamath Proof Explorer

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Syntax Definition wnfOLD 1709

Description: Extend wff definition to include the old not-free predicate. Obsolete as of 16-Sep-2021. (New usage is discouraged.)

**Hypotheses**
Ref	Expression
wph	wff 𝜑
vx	setvar 𝑥

**Assertion**
Ref	Expression
wnfOLD	wff Ⅎ𝑥𝜑

See definition df-nfOLD 1721 for more information.

Colors of variables: wff setvar class