"Partial" variable substitution not accounted for

Quelklef / fitch

Interactive proof assistant for Fitch-style natural deduction

https://maynards.site/fitch

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Closed Quelklef closed 5 years ago

Quelklef commented 5 years ago

Or:

│ 1: [a]Paa     assumption
├──────────
│ 2: ∃bPab      invalid step