This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.

Metamath Proof Explorer

Theorem pm2.61ii

Description: Inference eliminating two antecedents. (Contributed by NM, 4-Jan-1993) (Proof shortened by Josh Purinton, 29-Dec-2000)

Ref Expression
Hypotheses pm2.61ii.1 
|- ( -. ph -> ( -. ps -> ch ) )
pm2.61ii.2 
|- ( ph -> ch )
pm2.61ii.3 
|- ( ps -> ch )
Assertion pm2.61ii 
|- ch

Proof

Step Hyp Ref Expression
1 pm2.61ii.1 
 |-  ( -. ph -> ( -. ps -> ch ) )
2 pm2.61ii.2 
 |-  ( ph -> ch )
3 pm2.61ii.3 
 |-  ( ps -> ch )
4 1 3 pm2.61d2 
 |-  ( -. ph -> ch )
5 2 4 pm2.61i 
 |-  ch