Users' Mathboxes Mathbox for BJ < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >   Mathboxes  >  bj-nnclavius Unicode version

Theorem bj-nnclavius 13034
Description: Clavius law with doubly negated consequent. (Contributed by BJ, 4-Dec-2023.)
Assertion
Ref Expression
bj-nnclavius  |-  ( ( -.  ph  ->  ph )  ->  -.  -.  ph )

Proof of Theorem bj-nnclavius
StepHypRef Expression
1 con3 631 . 2  |-  ( ( -.  ph  ->  ph )  ->  ( -.  ph  ->  -. 
-.  ph ) )
21pm2.01d 607 1  |-  ( ( -.  ph  ->  ph )  ->  -.  -.  ph )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-in1 603  ax-in2 604
This theorem is referenced by:  bj-pm2.18st  13042
  Copyright terms: Public domain W3C validator