| Step | Hyp | Ref | Expression | 
						
							| 1 |  | simpr |  | 
						
							| 2 |  | unss1 |  | 
						
							| 3 |  | simpl1 |  | 
						
							| 4 |  | shss |  | 
						
							| 5 | 3 4 | syl |  | 
						
							| 6 |  | simpl3 |  | 
						
							| 7 |  | shss |  | 
						
							| 8 | 6 7 | syl |  | 
						
							| 9 | 5 8 | unssd |  | 
						
							| 10 |  | simpl2 |  | 
						
							| 11 |  | shss |  | 
						
							| 12 | 10 11 | syl |  | 
						
							| 13 | 12 8 | unssd |  | 
						
							| 14 |  | occon2 |  | 
						
							| 15 | 9 13 14 | syl2anc |  | 
						
							| 16 | 2 15 | syl5 |  | 
						
							| 17 | 1 16 | mpd |  | 
						
							| 18 |  | shjval |  | 
						
							| 19 | 3 6 18 | syl2anc |  | 
						
							| 20 |  | shjval |  | 
						
							| 21 | 10 6 20 | syl2anc |  | 
						
							| 22 | 17 19 21 | 3sstr4d |  |