| Intuitionistic Logic Explorer | 
      
      
      < Previous  
      Next >
      
       Nearby theorems  | 
  ||
| Mirrors > Home > ILE Home > Th. List > vprc | GIF version | ||
| Description: The universal class is not a member of itself (and thus is not a set). Proposition 5.21 of [TakeutiZaring] p. 21; our proof, however, does not depend on the Axiom of Regularity. (Contributed by NM, 23-Aug-1993.) | 
| Ref | Expression | 
|---|---|
| vprc | ⊢ ¬ V ∈ V | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | vnex 4164 | . 2 ⊢ ¬ ∃𝑥 𝑥 = V | |
| 2 | isset 2769 | . 2 ⊢ (V ∈ V ↔ ∃𝑥 𝑥 = V) | |
| 3 | 1, 2 | mtbir 672 | 1 ⊢ ¬ V ∈ V | 
| Colors of variables: wff set class | 
| Syntax hints: ¬ wn 3 = wceq 1364 ∃wex 1506 ∈ wcel 2167 Vcvv 2763 | 
| 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-in1 615 ax-in2 616 ax-5 1461 ax-gen 1463 ax-ie1 1507 ax-ie2 1508 ax-8 1518 ax-4 1524 ax-17 1540 ax-i9 1544 ax-ial 1548 ax-13 2169 ax-14 2170 ax-ext 2178 ax-sep 4151 | 
| This theorem depends on definitions: df-bi 117 df-tru 1367 df-fal 1370 df-nf 1475 df-sb 1777 df-clab 2183 df-cleq 2189 df-clel 2192 df-v 2765 | 
| This theorem is referenced by: nvel 4166 intexr 4183 intnexr 4184 abnex 4482 snnex 4483 ruALT 4587 dcextest 4617 iprc 4934 snexxph 7016 elfi2 7038 fi0 7041 | 
| Copyright terms: Public domain | W3C validator |