| Step | Hyp | Ref | Expression | 
						
							| 1 |  | uunT12p3.1 |  |-  ( ( ps /\ T. /\ ph ) -> ch ) | 
						
							| 2 |  | 3ancoma |  |-  ( ( ps /\ T. /\ ph ) <-> ( T. /\ ps /\ ph ) ) | 
						
							| 3 |  | 3anass |  |-  ( ( T. /\ ps /\ ph ) <-> ( T. /\ ( ps /\ ph ) ) ) | 
						
							| 4 | 2 3 | bitri |  |-  ( ( ps /\ T. /\ ph ) <-> ( T. /\ ( ps /\ ph ) ) ) | 
						
							| 5 |  | truan |  |-  ( ( T. /\ ( ps /\ ph ) ) <-> ( ps /\ ph ) ) | 
						
							| 6 | 4 5 | bitri |  |-  ( ( ps /\ T. /\ ph ) <-> ( ps /\ ph ) ) | 
						
							| 7 |  | ancom |  |-  ( ( ph /\ ps ) <-> ( ps /\ ph ) ) | 
						
							| 8 | 6 7 | bitr4i |  |-  ( ( ps /\ T. /\ ph ) <-> ( ph /\ ps ) ) | 
						
							| 9 | 8 1 | sylbir |  |-  ( ( ph /\ ps ) -> ch ) |