| Step | Hyp | Ref | Expression | 
						
							| 1 |  | axc16i.1 |  |-  ( x = z -> ( ph <-> ps ) ) | 
						
							| 2 |  | axc16i.2 |  |-  ( ps -> A. x ps ) | 
						
							| 3 |  | nfv |  |-  F/ z x = y | 
						
							| 4 |  | nfv |  |-  F/ x z = y | 
						
							| 5 |  | ax7 |  |-  ( x = z -> ( x = y -> z = y ) ) | 
						
							| 6 | 3 4 5 | cbv3 |  |-  ( A. x x = y -> A. z z = y ) | 
						
							| 7 |  | ax7 |  |-  ( z = x -> ( z = y -> x = y ) ) | 
						
							| 8 | 7 | spimvw |  |-  ( A. z z = y -> x = y ) | 
						
							| 9 |  | equcomi |  |-  ( x = y -> y = x ) | 
						
							| 10 |  | equcomi |  |-  ( z = y -> y = z ) | 
						
							| 11 |  | ax7 |  |-  ( y = z -> ( y = x -> z = x ) ) | 
						
							| 12 | 10 11 | syl |  |-  ( z = y -> ( y = x -> z = x ) ) | 
						
							| 13 | 9 12 | syl5com |  |-  ( x = y -> ( z = y -> z = x ) ) | 
						
							| 14 | 13 | alimdv |  |-  ( x = y -> ( A. z z = y -> A. z z = x ) ) | 
						
							| 15 | 8 14 | mpcom |  |-  ( A. z z = y -> A. z z = x ) | 
						
							| 16 |  | equcomi |  |-  ( z = x -> x = z ) | 
						
							| 17 | 16 | alimi |  |-  ( A. z z = x -> A. z x = z ) | 
						
							| 18 | 15 17 | syl |  |-  ( A. z z = y -> A. z x = z ) | 
						
							| 19 | 1 | biimpcd |  |-  ( ph -> ( x = z -> ps ) ) | 
						
							| 20 | 19 | alimdv |  |-  ( ph -> ( A. z x = z -> A. z ps ) ) | 
						
							| 21 | 2 | nf5i |  |-  F/ x ps | 
						
							| 22 |  | nfv |  |-  F/ z ph | 
						
							| 23 | 1 | biimprd |  |-  ( x = z -> ( ps -> ph ) ) | 
						
							| 24 | 16 23 | syl |  |-  ( z = x -> ( ps -> ph ) ) | 
						
							| 25 | 21 22 24 | cbv3 |  |-  ( A. z ps -> A. x ph ) | 
						
							| 26 | 20 25 | syl6com |  |-  ( A. z x = z -> ( ph -> A. x ph ) ) | 
						
							| 27 | 6 18 26 | 3syl |  |-  ( A. x x = y -> ( ph -> A. x ph ) ) |