| Intuitionistic Logic Explorer | 
      
      
      < Previous  
      Next >
      
       Nearby theorems  | 
  ||
| Mirrors > Home > ILE Home > Th. List > ferison | GIF version | ||
| Description: "Ferison", one of the syllogisms of Aristotelian logic. No 𝜑 is 𝜓, and some 𝜑 is 𝜒, therefore some 𝜒 is not 𝜓. (In Aristotelian notation, EIO-3: MeP and MiS therefore SoP.) (Contributed by David A. Wheeler, 28-Aug-2016.) (Revised by David A. Wheeler, 2-Sep-2016.) | 
| Ref | Expression | 
|---|---|
| ferison.maj | ⊢ ∀𝑥(𝜑 → ¬ 𝜓) | 
| ferison.min | ⊢ ∃𝑥(𝜑 ∧ 𝜒) | 
| Ref | Expression | 
|---|---|
| ferison | ⊢ ∃𝑥(𝜒 ∧ ¬ 𝜓) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | ferison.maj | . 2 ⊢ ∀𝑥(𝜑 → ¬ 𝜓) | |
| 2 | ferison.min | . 2 ⊢ ∃𝑥(𝜑 ∧ 𝜒) | |
| 3 | 1, 2 | datisi 2155 | 1 ⊢ ∃𝑥(𝜒 ∧ ¬ 𝜓) | 
| Colors of variables: wff set class | 
| Syntax hints: ¬ wn 3 → wi 4 ∧ wa 104 ∀wal 1362 ∃wex 1506 | 
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-5 1461 ax-gen 1463 ax-ie1 1507 ax-ie2 1508 ax-4 1524 ax-ial 1548 | 
| This theorem depends on definitions: df-bi 117 | 
| This theorem is referenced by: (None) | 
| Copyright terms: Public domain | W3C validator |