| Metamath Proof Explorer |
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Related theorems GIF version |
| Description: Extend wff definition to include the existential quantifier ("there exists"). |
| Ref | Expression |
|---|---|
| wph | wff φ |
| vx | set x |
| Ref | Expression |
|---|---|
| wex | wff ∃xφ |
| Colors of variables: wff set class |