| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 5oalem2.1 |  |-  A e. SH | 
						
							| 2 |  | 5oalem2.2 |  |-  B e. SH | 
						
							| 3 |  | 5oalem2.3 |  |-  C e. SH | 
						
							| 4 |  | 5oalem2.4 |  |-  D e. SH | 
						
							| 5 | 1 3 | shsvsi |  |-  ( ( x e. A /\ z e. C ) -> ( x -h z ) e. ( A +H C ) ) | 
						
							| 6 | 5 | ad2ant2r |  |-  ( ( ( x e. A /\ y e. B ) /\ ( z e. C /\ w e. D ) ) -> ( x -h z ) e. ( A +H C ) ) | 
						
							| 7 | 6 | adantr |  |-  ( ( ( ( x e. A /\ y e. B ) /\ ( z e. C /\ w e. D ) ) /\ ( x +h y ) = ( z +h w ) ) -> ( x -h z ) e. ( A +H C ) ) | 
						
							| 8 | 4 2 | shsvsi |  |-  ( ( w e. D /\ y e. B ) -> ( w -h y ) e. ( D +H B ) ) | 
						
							| 9 | 8 | ancoms |  |-  ( ( y e. B /\ w e. D ) -> ( w -h y ) e. ( D +H B ) ) | 
						
							| 10 | 2 4 | shscomi |  |-  ( B +H D ) = ( D +H B ) | 
						
							| 11 | 9 10 | eleqtrrdi |  |-  ( ( y e. B /\ w e. D ) -> ( w -h y ) e. ( B +H D ) ) | 
						
							| 12 | 11 | ad2ant2l |  |-  ( ( ( x e. A /\ y e. B ) /\ ( z e. C /\ w e. D ) ) -> ( w -h y ) e. ( B +H D ) ) | 
						
							| 13 | 12 | adantr |  |-  ( ( ( ( x e. A /\ y e. B ) /\ ( z e. C /\ w e. D ) ) /\ ( x +h y ) = ( z +h w ) ) -> ( w -h y ) e. ( B +H D ) ) | 
						
							| 14 | 1 | sheli |  |-  ( x e. A -> x e. ~H ) | 
						
							| 15 | 2 | sheli |  |-  ( y e. B -> y e. ~H ) | 
						
							| 16 | 14 15 | anim12i |  |-  ( ( x e. A /\ y e. B ) -> ( x e. ~H /\ y e. ~H ) ) | 
						
							| 17 | 3 | sheli |  |-  ( z e. C -> z e. ~H ) | 
						
							| 18 | 4 | sheli |  |-  ( w e. D -> w e. ~H ) | 
						
							| 19 | 17 18 | anim12i |  |-  ( ( z e. C /\ w e. D ) -> ( z e. ~H /\ w e. ~H ) ) | 
						
							| 20 | 16 19 | anim12i |  |-  ( ( ( x e. A /\ y e. B ) /\ ( z e. C /\ w e. D ) ) -> ( ( x e. ~H /\ y e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) ) | 
						
							| 21 |  | oveq1 |  |-  ( ( x +h y ) = ( z +h w ) -> ( ( x +h y ) -h ( z +h y ) ) = ( ( z +h w ) -h ( z +h y ) ) ) | 
						
							| 22 | 21 | adantl |  |-  ( ( ( ( x e. ~H /\ y e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) /\ ( x +h y ) = ( z +h w ) ) -> ( ( x +h y ) -h ( z +h y ) ) = ( ( z +h w ) -h ( z +h y ) ) ) | 
						
							| 23 |  | simpr |  |-  ( ( x e. ~H /\ y e. ~H ) -> y e. ~H ) | 
						
							| 24 | 23 | anim2i |  |-  ( ( z e. ~H /\ ( x e. ~H /\ y e. ~H ) ) -> ( z e. ~H /\ y e. ~H ) ) | 
						
							| 25 | 24 | ancoms |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ z e. ~H ) -> ( z e. ~H /\ y e. ~H ) ) | 
						
							| 26 |  | hvsub4 |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ ( z e. ~H /\ y e. ~H ) ) -> ( ( x +h y ) -h ( z +h y ) ) = ( ( x -h z ) +h ( y -h y ) ) ) | 
						
							| 27 | 25 26 | syldan |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ z e. ~H ) -> ( ( x +h y ) -h ( z +h y ) ) = ( ( x -h z ) +h ( y -h y ) ) ) | 
						
							| 28 |  | hvsubid |  |-  ( y e. ~H -> ( y -h y ) = 0h ) | 
						
							| 29 | 28 | oveq2d |  |-  ( y e. ~H -> ( ( x -h z ) +h ( y -h y ) ) = ( ( x -h z ) +h 0h ) ) | 
						
							| 30 | 29 | ad2antlr |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ z e. ~H ) -> ( ( x -h z ) +h ( y -h y ) ) = ( ( x -h z ) +h 0h ) ) | 
						
							| 31 |  | hvsubcl |  |-  ( ( x e. ~H /\ z e. ~H ) -> ( x -h z ) e. ~H ) | 
						
							| 32 |  | ax-hvaddid |  |-  ( ( x -h z ) e. ~H -> ( ( x -h z ) +h 0h ) = ( x -h z ) ) | 
						
							| 33 | 31 32 | syl |  |-  ( ( x e. ~H /\ z e. ~H ) -> ( ( x -h z ) +h 0h ) = ( x -h z ) ) | 
						
							| 34 | 33 | adantlr |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ z e. ~H ) -> ( ( x -h z ) +h 0h ) = ( x -h z ) ) | 
						
							| 35 | 27 30 34 | 3eqtrd |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ z e. ~H ) -> ( ( x +h y ) -h ( z +h y ) ) = ( x -h z ) ) | 
						
							| 36 | 35 | adantrr |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) -> ( ( x +h y ) -h ( z +h y ) ) = ( x -h z ) ) | 
						
							| 37 | 36 | adantr |  |-  ( ( ( ( x e. ~H /\ y e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) /\ ( x +h y ) = ( z +h w ) ) -> ( ( x +h y ) -h ( z +h y ) ) = ( x -h z ) ) | 
						
							| 38 |  | simpr |  |-  ( ( y e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( z e. ~H /\ w e. ~H ) ) | 
						
							| 39 |  | simpl |  |-  ( ( z e. ~H /\ w e. ~H ) -> z e. ~H ) | 
						
							| 40 | 39 | anim1i |  |-  ( ( ( z e. ~H /\ w e. ~H ) /\ y e. ~H ) -> ( z e. ~H /\ y e. ~H ) ) | 
						
							| 41 | 40 | ancoms |  |-  ( ( y e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( z e. ~H /\ y e. ~H ) ) | 
						
							| 42 |  | hvsub4 |  |-  ( ( ( z e. ~H /\ w e. ~H ) /\ ( z e. ~H /\ y e. ~H ) ) -> ( ( z +h w ) -h ( z +h y ) ) = ( ( z -h z ) +h ( w -h y ) ) ) | 
						
							| 43 | 38 41 42 | syl2anc |  |-  ( ( y e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( ( z +h w ) -h ( z +h y ) ) = ( ( z -h z ) +h ( w -h y ) ) ) | 
						
							| 44 |  | hvsubid |  |-  ( z e. ~H -> ( z -h z ) = 0h ) | 
						
							| 45 | 44 | oveq1d |  |-  ( z e. ~H -> ( ( z -h z ) +h ( w -h y ) ) = ( 0h +h ( w -h y ) ) ) | 
						
							| 46 | 45 | ad2antrl |  |-  ( ( y e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( ( z -h z ) +h ( w -h y ) ) = ( 0h +h ( w -h y ) ) ) | 
						
							| 47 |  | hvsubcl |  |-  ( ( w e. ~H /\ y e. ~H ) -> ( w -h y ) e. ~H ) | 
						
							| 48 |  | hvaddlid |  |-  ( ( w -h y ) e. ~H -> ( 0h +h ( w -h y ) ) = ( w -h y ) ) | 
						
							| 49 | 47 48 | syl |  |-  ( ( w e. ~H /\ y e. ~H ) -> ( 0h +h ( w -h y ) ) = ( w -h y ) ) | 
						
							| 50 | 49 | ancoms |  |-  ( ( y e. ~H /\ w e. ~H ) -> ( 0h +h ( w -h y ) ) = ( w -h y ) ) | 
						
							| 51 | 50 | adantrl |  |-  ( ( y e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( 0h +h ( w -h y ) ) = ( w -h y ) ) | 
						
							| 52 | 43 46 51 | 3eqtrd |  |-  ( ( y e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( ( z +h w ) -h ( z +h y ) ) = ( w -h y ) ) | 
						
							| 53 | 52 | adantll |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) -> ( ( z +h w ) -h ( z +h y ) ) = ( w -h y ) ) | 
						
							| 54 | 53 | adantr |  |-  ( ( ( ( x e. ~H /\ y e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) /\ ( x +h y ) = ( z +h w ) ) -> ( ( z +h w ) -h ( z +h y ) ) = ( w -h y ) ) | 
						
							| 55 | 22 37 54 | 3eqtr3d |  |-  ( ( ( ( x e. ~H /\ y e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) /\ ( x +h y ) = ( z +h w ) ) -> ( x -h z ) = ( w -h y ) ) | 
						
							| 56 | 55 | eleq1d |  |-  ( ( ( ( x e. ~H /\ y e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) /\ ( x +h y ) = ( z +h w ) ) -> ( ( x -h z ) e. ( B +H D ) <-> ( w -h y ) e. ( B +H D ) ) ) | 
						
							| 57 | 20 56 | sylan |  |-  ( ( ( ( x e. A /\ y e. B ) /\ ( z e. C /\ w e. D ) ) /\ ( x +h y ) = ( z +h w ) ) -> ( ( x -h z ) e. ( B +H D ) <-> ( w -h y ) e. ( B +H D ) ) ) | 
						
							| 58 | 13 57 | mpbird |  |-  ( ( ( ( x e. A /\ y e. B ) /\ ( z e. C /\ w e. D ) ) /\ ( x +h y ) = ( z +h w ) ) -> ( x -h z ) e. ( B +H D ) ) | 
						
							| 59 | 7 58 | elind |  |-  ( ( ( ( x e. A /\ y e. B ) /\ ( z e. C /\ w e. D ) ) /\ ( x +h y ) = ( z +h w ) ) -> ( x -h z ) e. ( ( A +H C ) i^i ( B +H D ) ) ) |