| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							ishlg.p | 
							 |-  P = ( Base ` G )  | 
						
						
							| 2 | 
							
								
							 | 
							ishlg.i | 
							 |-  I = ( Itv ` G )  | 
						
						
							| 3 | 
							
								
							 | 
							ishlg.k | 
							 |-  K = ( hlG ` G )  | 
						
						
							| 4 | 
							
								
							 | 
							ishlg.a | 
							 |-  ( ph -> A e. P )  | 
						
						
							| 5 | 
							
								
							 | 
							ishlg.b | 
							 |-  ( ph -> B e. P )  | 
						
						
							| 6 | 
							
								
							 | 
							ishlg.c | 
							 |-  ( ph -> C e. P )  | 
						
						
							| 7 | 
							
								
							 | 
							ishlg.g | 
							 |-  ( ph -> G e. V )  | 
						
						
							| 8 | 
							
								
							 | 
							simpl | 
							 |-  ( ( a = A /\ b = B ) -> a = A )  | 
						
						
							| 9 | 
							
								8
							 | 
							neeq1d | 
							 |-  ( ( a = A /\ b = B ) -> ( a =/= C <-> A =/= C ) )  | 
						
						
							| 10 | 
							
								
							 | 
							simpr | 
							 |-  ( ( a = A /\ b = B ) -> b = B )  | 
						
						
							| 11 | 
							
								10
							 | 
							neeq1d | 
							 |-  ( ( a = A /\ b = B ) -> ( b =/= C <-> B =/= C ) )  | 
						
						
							| 12 | 
							
								10
							 | 
							oveq2d | 
							 |-  ( ( a = A /\ b = B ) -> ( C I b ) = ( C I B ) )  | 
						
						
							| 13 | 
							
								8 12
							 | 
							eleq12d | 
							 |-  ( ( a = A /\ b = B ) -> ( a e. ( C I b ) <-> A e. ( C I B ) ) )  | 
						
						
							| 14 | 
							
								8
							 | 
							oveq2d | 
							 |-  ( ( a = A /\ b = B ) -> ( C I a ) = ( C I A ) )  | 
						
						
							| 15 | 
							
								10 14
							 | 
							eleq12d | 
							 |-  ( ( a = A /\ b = B ) -> ( b e. ( C I a ) <-> B e. ( C I A ) ) )  | 
						
						
							| 16 | 
							
								13 15
							 | 
							orbi12d | 
							 |-  ( ( a = A /\ b = B ) -> ( ( a e. ( C I b ) \/ b e. ( C I a ) ) <-> ( A e. ( C I B ) \/ B e. ( C I A ) ) ) )  | 
						
						
							| 17 | 
							
								9 11 16
							 | 
							3anbi123d | 
							 |-  ( ( a = A /\ b = B ) -> ( ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) <-> ( A =/= C /\ B =/= C /\ ( A e. ( C I B ) \/ B e. ( C I A ) ) ) ) )  | 
						
						
							| 18 | 
							
								
							 | 
							eqid | 
							 |-  { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) } = { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) } | 
						
						
							| 19 | 
							
								17 18
							 | 
							brab2a | 
							 |-  ( A { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) } B <-> ( ( A e. P /\ B e. P ) /\ ( A =/= C /\ B =/= C /\ ( A e. ( C I B ) \/ B e. ( C I A ) ) ) ) ) | 
						
						
							| 20 | 
							
								19
							 | 
							a1i | 
							 |-  ( ph -> ( A { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) } B <-> ( ( A e. P /\ B e. P ) /\ ( A =/= C /\ B =/= C /\ ( A e. ( C I B ) \/ B e. ( C I A ) ) ) ) ) ) | 
						
						
							| 21 | 
							
								
							 | 
							elex | 
							 |-  ( G e. V -> G e. _V )  | 
						
						
							| 22 | 
							
								
							 | 
							fveq2 | 
							 |-  ( g = G -> ( Base ` g ) = ( Base ` G ) )  | 
						
						
							| 23 | 
							
								22 1
							 | 
							eqtr4di | 
							 |-  ( g = G -> ( Base ` g ) = P )  | 
						
						
							| 24 | 
							
								23
							 | 
							eleq2d | 
							 |-  ( g = G -> ( a e. ( Base ` g ) <-> a e. P ) )  | 
						
						
							| 25 | 
							
								23
							 | 
							eleq2d | 
							 |-  ( g = G -> ( b e. ( Base ` g ) <-> b e. P ) )  | 
						
						
							| 26 | 
							
								24 25
							 | 
							anbi12d | 
							 |-  ( g = G -> ( ( a e. ( Base ` g ) /\ b e. ( Base ` g ) ) <-> ( a e. P /\ b e. P ) ) )  | 
						
						
							| 27 | 
							
								
							 | 
							fveq2 | 
							 |-  ( g = G -> ( Itv ` g ) = ( Itv ` G ) )  | 
						
						
							| 28 | 
							
								27 2
							 | 
							eqtr4di | 
							 |-  ( g = G -> ( Itv ` g ) = I )  | 
						
						
							| 29 | 
							
								28
							 | 
							oveqd | 
							 |-  ( g = G -> ( c ( Itv ` g ) b ) = ( c I b ) )  | 
						
						
							| 30 | 
							
								29
							 | 
							eleq2d | 
							 |-  ( g = G -> ( a e. ( c ( Itv ` g ) b ) <-> a e. ( c I b ) ) )  | 
						
						
							| 31 | 
							
								28
							 | 
							oveqd | 
							 |-  ( g = G -> ( c ( Itv ` g ) a ) = ( c I a ) )  | 
						
						
							| 32 | 
							
								31
							 | 
							eleq2d | 
							 |-  ( g = G -> ( b e. ( c ( Itv ` g ) a ) <-> b e. ( c I a ) ) )  | 
						
						
							| 33 | 
							
								30 32
							 | 
							orbi12d | 
							 |-  ( g = G -> ( ( a e. ( c ( Itv ` g ) b ) \/ b e. ( c ( Itv ` g ) a ) ) <-> ( a e. ( c I b ) \/ b e. ( c I a ) ) ) )  | 
						
						
							| 34 | 
							
								33
							 | 
							3anbi3d | 
							 |-  ( g = G -> ( ( a =/= c /\ b =/= c /\ ( a e. ( c ( Itv ` g ) b ) \/ b e. ( c ( Itv ` g ) a ) ) ) <-> ( a =/= c /\ b =/= c /\ ( a e. ( c I b ) \/ b e. ( c I a ) ) ) ) )  | 
						
						
							| 35 | 
							
								26 34
							 | 
							anbi12d | 
							 |-  ( g = G -> ( ( ( a e. ( Base ` g ) /\ b e. ( Base ` g ) ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c ( Itv ` g ) b ) \/ b e. ( c ( Itv ` g ) a ) ) ) ) <-> ( ( a e. P /\ b e. P ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c I b ) \/ b e. ( c I a ) ) ) ) ) )  | 
						
						
							| 36 | 
							
								35
							 | 
							opabbidv | 
							 |-  ( g = G -> { <. a , b >. | ( ( a e. ( Base ` g ) /\ b e. ( Base ` g ) ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c ( Itv ` g ) b ) \/ b e. ( c ( Itv ` g ) a ) ) ) ) } = { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c I b ) \/ b e. ( c I a ) ) ) ) } ) | 
						
						
							| 37 | 
							
								23 36
							 | 
							mpteq12dv | 
							 |-  ( g = G -> ( c e. ( Base ` g ) |-> { <. a , b >. | ( ( a e. ( Base ` g ) /\ b e. ( Base ` g ) ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c ( Itv ` g ) b ) \/ b e. ( c ( Itv ` g ) a ) ) ) ) } ) = ( c e. P |-> { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c I b ) \/ b e. ( c I a ) ) ) ) } ) ) | 
						
						
							| 38 | 
							
								
							 | 
							df-hlg | 
							 |-  hlG = ( g e. _V |-> ( c e. ( Base ` g ) |-> { <. a , b >. | ( ( a e. ( Base ` g ) /\ b e. ( Base ` g ) ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c ( Itv ` g ) b ) \/ b e. ( c ( Itv ` g ) a ) ) ) ) } ) ) | 
						
						
							| 39 | 
							
								37 38 1
							 | 
							mptfvmpt | 
							 |-  ( G e. _V -> ( hlG ` G ) = ( c e. P |-> { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c I b ) \/ b e. ( c I a ) ) ) ) } ) ) | 
						
						
							| 40 | 
							
								7 21 39
							 | 
							3syl | 
							 |-  ( ph -> ( hlG ` G ) = ( c e. P |-> { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c I b ) \/ b e. ( c I a ) ) ) ) } ) ) | 
						
						
							| 41 | 
							
								3 40
							 | 
							eqtrid | 
							 |-  ( ph -> K = ( c e. P |-> { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c I b ) \/ b e. ( c I a ) ) ) ) } ) ) | 
						
						
							| 42 | 
							
								
							 | 
							neeq2 | 
							 |-  ( c = C -> ( a =/= c <-> a =/= C ) )  | 
						
						
							| 43 | 
							
								
							 | 
							neeq2 | 
							 |-  ( c = C -> ( b =/= c <-> b =/= C ) )  | 
						
						
							| 44 | 
							
								
							 | 
							oveq1 | 
							 |-  ( c = C -> ( c I b ) = ( C I b ) )  | 
						
						
							| 45 | 
							
								44
							 | 
							eleq2d | 
							 |-  ( c = C -> ( a e. ( c I b ) <-> a e. ( C I b ) ) )  | 
						
						
							| 46 | 
							
								
							 | 
							oveq1 | 
							 |-  ( c = C -> ( c I a ) = ( C I a ) )  | 
						
						
							| 47 | 
							
								46
							 | 
							eleq2d | 
							 |-  ( c = C -> ( b e. ( c I a ) <-> b e. ( C I a ) ) )  | 
						
						
							| 48 | 
							
								45 47
							 | 
							orbi12d | 
							 |-  ( c = C -> ( ( a e. ( c I b ) \/ b e. ( c I a ) ) <-> ( a e. ( C I b ) \/ b e. ( C I a ) ) ) )  | 
						
						
							| 49 | 
							
								42 43 48
							 | 
							3anbi123d | 
							 |-  ( c = C -> ( ( a =/= c /\ b =/= c /\ ( a e. ( c I b ) \/ b e. ( c I a ) ) ) <-> ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) )  | 
						
						
							| 50 | 
							
								49
							 | 
							anbi2d | 
							 |-  ( c = C -> ( ( ( a e. P /\ b e. P ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c I b ) \/ b e. ( c I a ) ) ) ) <-> ( ( a e. P /\ b e. P ) /\ ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) ) )  | 
						
						
							| 51 | 
							
								50
							 | 
							opabbidv | 
							 |-  ( c = C -> { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c I b ) \/ b e. ( c I a ) ) ) ) } = { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) } ) | 
						
						
							| 52 | 
							
								51
							 | 
							adantl | 
							 |-  ( ( ph /\ c = C ) -> { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= c /\ b =/= c /\ ( a e. ( c I b ) \/ b e. ( c I a ) ) ) ) } = { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) } ) | 
						
						
							| 53 | 
							
								1
							 | 
							fvexi | 
							 |-  P e. _V  | 
						
						
							| 54 | 
							
								53 53
							 | 
							xpex | 
							 |-  ( P X. P ) e. _V  | 
						
						
							| 55 | 
							
								
							 | 
							opabssxp | 
							 |-  { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) } C_ ( P X. P ) | 
						
						
							| 56 | 
							
								54 55
							 | 
							ssexi | 
							 |-  { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) } e. _V | 
						
						
							| 57 | 
							
								56
							 | 
							a1i | 
							 |-  ( ph -> { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) } e. _V ) | 
						
						
							| 58 | 
							
								41 52 6 57
							 | 
							fvmptd | 
							 |-  ( ph -> ( K ` C ) = { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) } ) | 
						
						
							| 59 | 
							
								58
							 | 
							breqd | 
							 |-  ( ph -> ( A ( K ` C ) B <-> A { <. a , b >. | ( ( a e. P /\ b e. P ) /\ ( a =/= C /\ b =/= C /\ ( a e. ( C I b ) \/ b e. ( C I a ) ) ) ) } B ) ) | 
						
						
							| 60 | 
							
								4 5
							 | 
							jca | 
							 |-  ( ph -> ( A e. P /\ B e. P ) )  | 
						
						
							| 61 | 
							
								60
							 | 
							biantrurd | 
							 |-  ( ph -> ( ( A =/= C /\ B =/= C /\ ( A e. ( C I B ) \/ B e. ( C I A ) ) ) <-> ( ( A e. P /\ B e. P ) /\ ( A =/= C /\ B =/= C /\ ( A e. ( C I B ) \/ B e. ( C I A ) ) ) ) ) )  | 
						
						
							| 62 | 
							
								20 59 61
							 | 
							3bitr4d | 
							 |-  ( ph -> ( A ( K ` C ) B <-> ( A =/= C /\ B =/= C /\ ( A e. ( C I B ) \/ B e. ( C I A ) ) ) ) )  |