Metamath Proof Explorer


Theorem quantgodel

Description: There can be no formula asserting its own non-universality, in parallel to bj-babygodel ; proof path is shorter but relying on a property of specialization which provability predicates do not have. For a matching proof, see quantgodelALT . (Contributed by Ender Ting, 9-May-2026)

Ref Expression
Hypothesis quantgodel.s
|- ( ph <-> -. A. x ph )
Assertion quantgodel
|- F.

Proof

Step Hyp Ref Expression
1 quantgodel.s
 |-  ( ph <-> -. A. x ph )
2 sp
 |-  ( A. x ph -> ph )
3 2 1 sylib
 |-  ( A. x ph -> -. A. x ph )
4 3 pm2.01i
 |-  -. A. x ph
5 4 1 mpbir
 |-  ph
6 5 ax-gen
 |-  A. x ph
7 6 4 pm2.24ii
 |-  F.