Metamath Proof Explorer


Theorem wl-luk-con4i

Description: Inference rule. Copy of con4i with a different proof. (Contributed by Wolf Lammen, 17-Dec-2018) (New usage is discouraged.) (Proof modification is discouraged.)

Ref Expression
Hypothesis wl-luk-con4i.1
|- ( -. ph -> -. ps )
Assertion wl-luk-con4i
|- ( ps -> ph )

Proof

Step Hyp Ref Expression
1 wl-luk-con4i.1
 |-  ( -. ph -> -. ps )
2 ax-luk3
 |-  ( ps -> ( -. ps -> ph ) )
3 1 2 wl-luk-imtrid
 |-  ( ps -> ( -. ph -> ph ) )
4 3 wl-luk-pm2.18d
 |-  ( ps -> ph )