| Step | Hyp | Ref | Expression | 
						
							| 1 |  | excom |  |-  ( E. z E. w E. x E. y ( v = <. w , z >. /\ ( w = <. x , y >. /\ ph ) ) <-> E. w E. z E. x E. y ( v = <. w , z >. /\ ( w = <. x , y >. /\ ph ) ) ) | 
						
							| 2 |  | exrot4 |  |-  ( E. z E. w E. x E. y ( v = <. w , z >. /\ ( w = <. x , y >. /\ ph ) ) <-> E. x E. y E. z E. w ( v = <. w , z >. /\ ( w = <. x , y >. /\ ph ) ) ) | 
						
							| 3 |  | opeq1 |  |-  ( w = <. x , y >. -> <. w , z >. = <. <. x , y >. , z >. ) | 
						
							| 4 | 3 | eqeq2d |  |-  ( w = <. x , y >. -> ( v = <. w , z >. <-> v = <. <. x , y >. , z >. ) ) | 
						
							| 5 | 4 | pm5.32ri |  |-  ( ( v = <. w , z >. /\ w = <. x , y >. ) <-> ( v = <. <. x , y >. , z >. /\ w = <. x , y >. ) ) | 
						
							| 6 | 5 | anbi1i |  |-  ( ( ( v = <. w , z >. /\ w = <. x , y >. ) /\ ph ) <-> ( ( v = <. <. x , y >. , z >. /\ w = <. x , y >. ) /\ ph ) ) | 
						
							| 7 |  | anass |  |-  ( ( ( v = <. w , z >. /\ w = <. x , y >. ) /\ ph ) <-> ( v = <. w , z >. /\ ( w = <. x , y >. /\ ph ) ) ) | 
						
							| 8 |  | an32 |  |-  ( ( ( v = <. <. x , y >. , z >. /\ w = <. x , y >. ) /\ ph ) <-> ( ( v = <. <. x , y >. , z >. /\ ph ) /\ w = <. x , y >. ) ) | 
						
							| 9 | 6 7 8 | 3bitr3i |  |-  ( ( v = <. w , z >. /\ ( w = <. x , y >. /\ ph ) ) <-> ( ( v = <. <. x , y >. , z >. /\ ph ) /\ w = <. x , y >. ) ) | 
						
							| 10 | 9 | exbii |  |-  ( E. w ( v = <. w , z >. /\ ( w = <. x , y >. /\ ph ) ) <-> E. w ( ( v = <. <. x , y >. , z >. /\ ph ) /\ w = <. x , y >. ) ) | 
						
							| 11 |  | opex |  |-  <. x , y >. e. _V | 
						
							| 12 | 11 | isseti |  |-  E. w w = <. x , y >. | 
						
							| 13 |  | 19.42v |  |-  ( E. w ( ( v = <. <. x , y >. , z >. /\ ph ) /\ w = <. x , y >. ) <-> ( ( v = <. <. x , y >. , z >. /\ ph ) /\ E. w w = <. x , y >. ) ) | 
						
							| 14 | 12 13 | mpbiran2 |  |-  ( E. w ( ( v = <. <. x , y >. , z >. /\ ph ) /\ w = <. x , y >. ) <-> ( v = <. <. x , y >. , z >. /\ ph ) ) | 
						
							| 15 | 10 14 | bitri |  |-  ( E. w ( v = <. w , z >. /\ ( w = <. x , y >. /\ ph ) ) <-> ( v = <. <. x , y >. , z >. /\ ph ) ) | 
						
							| 16 | 15 | 3exbii |  |-  ( E. x E. y E. z E. w ( v = <. w , z >. /\ ( w = <. x , y >. /\ ph ) ) <-> E. x E. y E. z ( v = <. <. x , y >. , z >. /\ ph ) ) | 
						
							| 17 | 2 16 | bitri |  |-  ( E. z E. w E. x E. y ( v = <. w , z >. /\ ( w = <. x , y >. /\ ph ) ) <-> E. x E. y E. z ( v = <. <. x , y >. , z >. /\ ph ) ) | 
						
							| 18 |  | 19.42vv |  |-  ( E. x E. y ( v = <. w , z >. /\ ( w = <. x , y >. /\ ph ) ) <-> ( v = <. w , z >. /\ E. x E. y ( w = <. x , y >. /\ ph ) ) ) | 
						
							| 19 | 18 | 2exbii |  |-  ( E. w E. z E. x E. y ( v = <. w , z >. /\ ( w = <. x , y >. /\ ph ) ) <-> E. w E. z ( v = <. w , z >. /\ E. x E. y ( w = <. x , y >. /\ ph ) ) ) | 
						
							| 20 | 1 17 19 | 3bitr3i |  |-  ( E. x E. y E. z ( v = <. <. x , y >. , z >. /\ ph ) <-> E. w E. z ( v = <. w , z >. /\ E. x E. y ( w = <. x , y >. /\ ph ) ) ) | 
						
							| 21 | 20 | abbii |  |-  { v | E. x E. y E. z ( v = <. <. x , y >. , z >. /\ ph ) } = { v | E. w E. z ( v = <. w , z >. /\ E. x E. y ( w = <. x , y >. /\ ph ) ) } | 
						
							| 22 |  | df-oprab |  |-  { <. <. x , y >. , z >. | ph } = { v | E. x E. y E. z ( v = <. <. x , y >. , z >. /\ ph ) } | 
						
							| 23 |  | df-opab |  |-  { <. w , z >. | E. x E. y ( w = <. x , y >. /\ ph ) } = { v | E. w E. z ( v = <. w , z >. /\ E. x E. y ( w = <. x , y >. /\ ph ) ) } | 
						
							| 24 | 21 22 23 | 3eqtr4i |  |-  { <. <. x , y >. , z >. | ph } = { <. w , z >. | E. x E. y ( w = <. x , y >. /\ ph ) } |