| Metamath Proof Explorer |
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Related theorems GIF version |
| Description: Extend wff definition to include 3-way conjunction ('and'). |
| Ref | Expression |
|---|---|
| wph | wff φ |
| wps | wff ψ |
| wch | wff χ |
| Ref | Expression |
|---|---|
| w3a | wff (φ ⋀ ψ ⋀ χ) |
| Colors of variables: wff set class |