| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eqid |  | 
						
							| 2 |  | eqid |  | 
						
							| 3 | 1 2 | hartogslem1 |  | 
						
							| 4 | 3 | simp2i |  | 
						
							| 5 | 3 | simp1i |  | 
						
							| 6 |  | sqxpexg |  | 
						
							| 7 | 6 | pwexd |  | 
						
							| 8 |  | ssexg |  | 
						
							| 9 | 5 7 8 | sylancr |  | 
						
							| 10 |  | funex |  | 
						
							| 11 | 4 9 10 | sylancr |  | 
						
							| 12 |  | funfn |  | 
						
							| 13 | 4 12 | mpbi |  | 
						
							| 14 | 13 | a1i |  | 
						
							| 15 | 3 | simp3i |  | 
						
							| 16 |  | harval |  | 
						
							| 17 | 15 16 | eqtr4d |  | 
						
							| 18 |  | df-fo |  | 
						
							| 19 | 14 17 18 | sylanbrc |  | 
						
							| 20 |  | fowdom |  | 
						
							| 21 | 11 19 20 | syl2anc |  | 
						
							| 22 |  | ssdomg |  | 
						
							| 23 | 7 5 22 | mpisyl |  | 
						
							| 24 |  | domwdom |  | 
						
							| 25 | 23 24 | syl |  | 
						
							| 26 |  | wdomtr |  | 
						
							| 27 | 21 25 26 | syl2anc |  |