| Step | Hyp | Ref | Expression | 
						
							| 1 |  | psgndif.p |  | 
						
							| 2 |  | psgndif.s |  | 
						
							| 3 |  | psgndif.z |  | 
						
							| 4 |  | eqid |  | 
						
							| 5 |  | eqid |  | 
						
							| 6 |  | eqid |  | 
						
							| 7 |  | eqid |  | 
						
							| 8 | 1 4 5 6 7 | psgnfix2 |  | 
						
							| 9 | 8 | imp |  | 
						
							| 10 | 9 | ad2antrr |  | 
						
							| 11 | 1 4 5 6 7 | psgndiflemA |  | 
						
							| 12 | 11 | imp |  | 
						
							| 13 | 12 | 3anassrs |  | 
						
							| 14 | 13 | adantlrr |  | 
						
							| 15 |  | eqeq1 |  | 
						
							| 16 | 15 | ad2antll |  | 
						
							| 17 | 16 | adantr |  | 
						
							| 18 | 14 17 | sylibrd |  | 
						
							| 19 | 18 | ralrimiva |  | 
						
							| 20 | 10 19 | r19.29imd |  | 
						
							| 21 | 20 | rexlimdva2 |  | 
						
							| 22 | 1 4 5 | psgnfix1 |  | 
						
							| 23 | 22 | imp |  | 
						
							| 24 | 23 | ad2antrr |  | 
						
							| 25 |  | simp-4l |  | 
						
							| 26 |  | simpr |  | 
						
							| 27 | 26 | adantr |  | 
						
							| 28 |  | simpr |  | 
						
							| 29 |  | simp-4r |  | 
						
							| 30 | 27 28 29 | 3jca |  | 
						
							| 31 |  | simpr |  | 
						
							| 32 | 31 | ad2antrr |  | 
						
							| 33 | 25 30 32 11 | syl3c |  | 
						
							| 34 | 33 | eqcomd |  | 
						
							| 35 | 34 | ex |  | 
						
							| 36 | 35 | adantlrr |  | 
						
							| 37 |  | eqeq1 |  | 
						
							| 38 | 37 | ad2antll |  | 
						
							| 39 | 38 | adantr |  | 
						
							| 40 | 36 39 | sylibrd |  | 
						
							| 41 | 40 | ralrimiva |  | 
						
							| 42 | 24 41 | r19.29imd |  | 
						
							| 43 | 42 | rexlimdva2 |  | 
						
							| 44 | 21 43 | impbid |  | 
						
							| 45 | 44 | iotabidv |  | 
						
							| 46 |  | diffi |  | 
						
							| 47 | 46 | ad2antrr |  | 
						
							| 48 |  | eqid |  | 
						
							| 49 |  | eqid |  | 
						
							| 50 |  | eqid |  | 
						
							| 51 | 1 48 49 50 | symgfixelsi |  | 
						
							| 52 | 51 | adantll |  | 
						
							| 53 | 5 49 4 3 | psgnvalfi |  | 
						
							| 54 | 47 52 53 | syl2anc |  | 
						
							| 55 |  | simpl |  | 
						
							| 56 |  | elrabi |  | 
						
							| 57 | 6 1 7 2 | psgnvalfi |  | 
						
							| 58 | 55 56 57 | syl2an |  | 
						
							| 59 | 45 54 58 | 3eqtr4d |  | 
						
							| 60 | 59 | ex |  |