| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 3oalem1.1 |  |-  B e. CH | 
						
							| 2 |  | 3oalem1.2 |  |-  C e. CH | 
						
							| 3 |  | 3oalem1.3 |  |-  R e. CH | 
						
							| 4 |  | 3oalem1.4 |  |-  S e. CH | 
						
							| 5 |  | simplll |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> x e. B ) | 
						
							| 6 |  | simpllr |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> y e. R ) | 
						
							| 7 | 1 2 3 4 | 3oalem1 |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( ( ( x e. ~H /\ y e. ~H ) /\ v e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) ) | 
						
							| 8 |  | hvaddsub12 |  |-  ( ( y e. ~H /\ w e. ~H /\ w e. ~H ) -> ( y +h ( w -h w ) ) = ( w +h ( y -h w ) ) ) | 
						
							| 9 | 8 | 3anidm23 |  |-  ( ( y e. ~H /\ w e. ~H ) -> ( y +h ( w -h w ) ) = ( w +h ( y -h w ) ) ) | 
						
							| 10 |  | hvsubid |  |-  ( w e. ~H -> ( w -h w ) = 0h ) | 
						
							| 11 | 10 | oveq2d |  |-  ( w e. ~H -> ( y +h ( w -h w ) ) = ( y +h 0h ) ) | 
						
							| 12 |  | ax-hvaddid |  |-  ( y e. ~H -> ( y +h 0h ) = y ) | 
						
							| 13 | 11 12 | sylan9eqr |  |-  ( ( y e. ~H /\ w e. ~H ) -> ( y +h ( w -h w ) ) = y ) | 
						
							| 14 | 9 13 | eqtr3d |  |-  ( ( y e. ~H /\ w e. ~H ) -> ( w +h ( y -h w ) ) = y ) | 
						
							| 15 | 14 | ad2ant2l |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) -> ( w +h ( y -h w ) ) = y ) | 
						
							| 16 | 15 | adantlr |  |-  ( ( ( ( x e. ~H /\ y e. ~H ) /\ v e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) -> ( w +h ( y -h w ) ) = y ) | 
						
							| 17 | 7 16 | syl |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( w +h ( y -h w ) ) = y ) | 
						
							| 18 |  | simprlr |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> w e. S ) | 
						
							| 19 |  | eqtr2 |  |-  ( ( v = ( x +h y ) /\ v = ( z +h w ) ) -> ( x +h y ) = ( z +h w ) ) | 
						
							| 20 | 19 | oveq1d |  |-  ( ( v = ( x +h y ) /\ v = ( z +h w ) ) -> ( ( x +h y ) -h ( x +h w ) ) = ( ( z +h w ) -h ( x +h w ) ) ) | 
						
							| 21 | 20 | ad2ant2l |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( ( x +h y ) -h ( x +h w ) ) = ( ( z +h w ) -h ( x +h w ) ) ) | 
						
							| 22 |  | simpl |  |-  ( ( x e. ~H /\ y e. ~H ) -> x e. ~H ) | 
						
							| 23 | 22 | anim1i |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ w e. ~H ) -> ( x e. ~H /\ w e. ~H ) ) | 
						
							| 24 |  | hvsub4 |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ ( x e. ~H /\ w e. ~H ) ) -> ( ( x +h y ) -h ( x +h w ) ) = ( ( x -h x ) +h ( y -h w ) ) ) | 
						
							| 25 | 23 24 | syldan |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ w e. ~H ) -> ( ( x +h y ) -h ( x +h w ) ) = ( ( x -h x ) +h ( y -h w ) ) ) | 
						
							| 26 |  | hvsubid |  |-  ( x e. ~H -> ( x -h x ) = 0h ) | 
						
							| 27 | 26 | ad2antrr |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ w e. ~H ) -> ( x -h x ) = 0h ) | 
						
							| 28 | 27 | oveq1d |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ w e. ~H ) -> ( ( x -h x ) +h ( y -h w ) ) = ( 0h +h ( y -h w ) ) ) | 
						
							| 29 |  | hvsubcl |  |-  ( ( y e. ~H /\ w e. ~H ) -> ( y -h w ) e. ~H ) | 
						
							| 30 |  | hvaddlid |  |-  ( ( y -h w ) e. ~H -> ( 0h +h ( y -h w ) ) = ( y -h w ) ) | 
						
							| 31 | 29 30 | syl |  |-  ( ( y e. ~H /\ w e. ~H ) -> ( 0h +h ( y -h w ) ) = ( y -h w ) ) | 
						
							| 32 | 31 | adantll |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ w e. ~H ) -> ( 0h +h ( y -h w ) ) = ( y -h w ) ) | 
						
							| 33 | 25 28 32 | 3eqtrd |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ w e. ~H ) -> ( ( x +h y ) -h ( x +h w ) ) = ( y -h w ) ) | 
						
							| 34 | 33 | ad2ant2rl |  |-  ( ( ( ( x e. ~H /\ y e. ~H ) /\ v e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) -> ( ( x +h y ) -h ( x +h w ) ) = ( y -h w ) ) | 
						
							| 35 | 7 34 | syl |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( ( x +h y ) -h ( x +h w ) ) = ( y -h w ) ) | 
						
							| 36 |  | simpr |  |-  ( ( x e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( z e. ~H /\ w e. ~H ) ) | 
						
							| 37 |  | simpr |  |-  ( ( z e. ~H /\ w e. ~H ) -> w e. ~H ) | 
						
							| 38 | 37 | anim2i |  |-  ( ( x e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( x e. ~H /\ w e. ~H ) ) | 
						
							| 39 |  | hvsub4 |  |-  ( ( ( z e. ~H /\ w e. ~H ) /\ ( x e. ~H /\ w e. ~H ) ) -> ( ( z +h w ) -h ( x +h w ) ) = ( ( z -h x ) +h ( w -h w ) ) ) | 
						
							| 40 | 36 38 39 | syl2anc |  |-  ( ( x e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( ( z +h w ) -h ( x +h w ) ) = ( ( z -h x ) +h ( w -h w ) ) ) | 
						
							| 41 | 10 | ad2antll |  |-  ( ( x e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( w -h w ) = 0h ) | 
						
							| 42 | 41 | oveq2d |  |-  ( ( x e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( ( z -h x ) +h ( w -h w ) ) = ( ( z -h x ) +h 0h ) ) | 
						
							| 43 |  | hvsubcl |  |-  ( ( z e. ~H /\ x e. ~H ) -> ( z -h x ) e. ~H ) | 
						
							| 44 |  | ax-hvaddid |  |-  ( ( z -h x ) e. ~H -> ( ( z -h x ) +h 0h ) = ( z -h x ) ) | 
						
							| 45 | 43 44 | syl |  |-  ( ( z e. ~H /\ x e. ~H ) -> ( ( z -h x ) +h 0h ) = ( z -h x ) ) | 
						
							| 46 | 45 | ancoms |  |-  ( ( x e. ~H /\ z e. ~H ) -> ( ( z -h x ) +h 0h ) = ( z -h x ) ) | 
						
							| 47 | 46 | adantrr |  |-  ( ( x e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( ( z -h x ) +h 0h ) = ( z -h x ) ) | 
						
							| 48 | 40 42 47 | 3eqtrd |  |-  ( ( x e. ~H /\ ( z e. ~H /\ w e. ~H ) ) -> ( ( z +h w ) -h ( x +h w ) ) = ( z -h x ) ) | 
						
							| 49 | 48 | adantlr |  |-  ( ( ( x e. ~H /\ y e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) -> ( ( z +h w ) -h ( x +h w ) ) = ( z -h x ) ) | 
						
							| 50 | 49 | adantlr |  |-  ( ( ( ( x e. ~H /\ y e. ~H ) /\ v e. ~H ) /\ ( z e. ~H /\ w e. ~H ) ) -> ( ( z +h w ) -h ( x +h w ) ) = ( z -h x ) ) | 
						
							| 51 | 7 50 | syl |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( ( z +h w ) -h ( x +h w ) ) = ( z -h x ) ) | 
						
							| 52 | 21 35 51 | 3eqtr3d |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( y -h w ) = ( z -h x ) ) | 
						
							| 53 |  | simpll |  |-  ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) -> x e. B ) | 
						
							| 54 |  | simpll |  |-  ( ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) -> z e. C ) | 
						
							| 55 | 2 | chshii |  |-  C e. SH | 
						
							| 56 | 1 | chshii |  |-  B e. SH | 
						
							| 57 | 55 56 | shsvsi |  |-  ( ( z e. C /\ x e. B ) -> ( z -h x ) e. ( C +H B ) ) | 
						
							| 58 | 57 | ancoms |  |-  ( ( x e. B /\ z e. C ) -> ( z -h x ) e. ( C +H B ) ) | 
						
							| 59 | 56 55 | shscomi |  |-  ( B +H C ) = ( C +H B ) | 
						
							| 60 | 58 59 | eleqtrrdi |  |-  ( ( x e. B /\ z e. C ) -> ( z -h x ) e. ( B +H C ) ) | 
						
							| 61 | 53 54 60 | syl2an |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( z -h x ) e. ( B +H C ) ) | 
						
							| 62 | 52 61 | eqeltrd |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( y -h w ) e. ( B +H C ) ) | 
						
							| 63 |  | simplr |  |-  ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) -> y e. R ) | 
						
							| 64 |  | simplr |  |-  ( ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) -> w e. S ) | 
						
							| 65 | 3 | chshii |  |-  R e. SH | 
						
							| 66 | 4 | chshii |  |-  S e. SH | 
						
							| 67 | 65 66 | shsvsi |  |-  ( ( y e. R /\ w e. S ) -> ( y -h w ) e. ( R +H S ) ) | 
						
							| 68 | 63 64 67 | syl2an |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( y -h w ) e. ( R +H S ) ) | 
						
							| 69 | 62 68 | elind |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( y -h w ) e. ( ( B +H C ) i^i ( R +H S ) ) ) | 
						
							| 70 | 56 55 | shscli |  |-  ( B +H C ) e. SH | 
						
							| 71 | 65 66 | shscli |  |-  ( R +H S ) e. SH | 
						
							| 72 | 70 71 | shincli |  |-  ( ( B +H C ) i^i ( R +H S ) ) e. SH | 
						
							| 73 | 66 72 | shsvai |  |-  ( ( w e. S /\ ( y -h w ) e. ( ( B +H C ) i^i ( R +H S ) ) ) -> ( w +h ( y -h w ) ) e. ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) | 
						
							| 74 | 18 69 73 | syl2anc |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( w +h ( y -h w ) ) e. ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) | 
						
							| 75 | 17 74 | eqeltrrd |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> y e. ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) | 
						
							| 76 | 6 75 | elind |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> y e. ( R i^i ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) ) | 
						
							| 77 | 66 72 | shscli |  |-  ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) e. SH | 
						
							| 78 | 65 77 | shincli |  |-  ( R i^i ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) e. SH | 
						
							| 79 | 56 78 | shsvai |  |-  ( ( x e. B /\ y e. ( R i^i ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) ) -> ( x +h y ) e. ( B +H ( R i^i ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) ) ) | 
						
							| 80 | 5 76 79 | syl2anc |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( x +h y ) e. ( B +H ( R i^i ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) ) ) | 
						
							| 81 |  | eleq1 |  |-  ( v = ( x +h y ) -> ( v e. ( B +H ( R i^i ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) ) <-> ( x +h y ) e. ( B +H ( R i^i ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) ) ) ) | 
						
							| 82 | 81 | ad2antlr |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> ( v e. ( B +H ( R i^i ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) ) <-> ( x +h y ) e. ( B +H ( R i^i ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) ) ) ) | 
						
							| 83 | 80 82 | mpbird |  |-  ( ( ( ( x e. B /\ y e. R ) /\ v = ( x +h y ) ) /\ ( ( z e. C /\ w e. S ) /\ v = ( z +h w ) ) ) -> v e. ( B +H ( R i^i ( S +H ( ( B +H C ) i^i ( R +H S ) ) ) ) ) ) |