| Step | Hyp | Ref | Expression | 
						
							| 1 |  | dvhvaddcl.h |  |-  H = ( LHyp ` K ) | 
						
							| 2 |  | dvhvaddcl.t |  |-  T = ( ( LTrn ` K ) ` W ) | 
						
							| 3 |  | dvhvaddcl.e |  |-  E = ( ( TEndo ` K ) ` W ) | 
						
							| 4 |  | dvhvaddcl.u |  |-  U = ( ( DVecH ` K ) ` W ) | 
						
							| 5 |  | dvhvaddcl.d |  |-  D = ( Scalar ` U ) | 
						
							| 6 |  | dvhvaddcl.p |  |-  .+^ = ( +g ` D ) | 
						
							| 7 |  | dvhvaddcl.a |  |-  .+ = ( +g ` U ) | 
						
							| 8 |  | coass |  |-  ( ( ( 1st ` F ) o. ( 1st ` G ) ) o. ( 1st ` I ) ) = ( ( 1st ` F ) o. ( ( 1st ` G ) o. ( 1st ` I ) ) ) | 
						
							| 9 | 1 2 3 4 5 7 6 | dvhvadd |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) ) ) -> ( F .+ G ) = <. ( ( 1st ` F ) o. ( 1st ` G ) ) , ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) >. ) | 
						
							| 10 | 9 | 3adantr3 |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( F .+ G ) = <. ( ( 1st ` F ) o. ( 1st ` G ) ) , ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) >. ) | 
						
							| 11 | 10 | fveq2d |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( 1st ` ( F .+ G ) ) = ( 1st ` <. ( ( 1st ` F ) o. ( 1st ` G ) ) , ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) >. ) ) | 
						
							| 12 |  | fvex |  |-  ( 1st ` F ) e. _V | 
						
							| 13 |  | fvex |  |-  ( 1st ` G ) e. _V | 
						
							| 14 | 12 13 | coex |  |-  ( ( 1st ` F ) o. ( 1st ` G ) ) e. _V | 
						
							| 15 |  | ovex |  |-  ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) e. _V | 
						
							| 16 | 14 15 | op1st |  |-  ( 1st ` <. ( ( 1st ` F ) o. ( 1st ` G ) ) , ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) >. ) = ( ( 1st ` F ) o. ( 1st ` G ) ) | 
						
							| 17 | 11 16 | eqtrdi |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( 1st ` ( F .+ G ) ) = ( ( 1st ` F ) o. ( 1st ` G ) ) ) | 
						
							| 18 | 17 | coeq1d |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( ( 1st ` ( F .+ G ) ) o. ( 1st ` I ) ) = ( ( ( 1st ` F ) o. ( 1st ` G ) ) o. ( 1st ` I ) ) ) | 
						
							| 19 | 1 2 3 4 5 7 6 | dvhvadd |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( G .+ I ) = <. ( ( 1st ` G ) o. ( 1st ` I ) ) , ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) >. ) | 
						
							| 20 | 19 | 3adantr1 |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( G .+ I ) = <. ( ( 1st ` G ) o. ( 1st ` I ) ) , ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) >. ) | 
						
							| 21 | 20 | fveq2d |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( 1st ` ( G .+ I ) ) = ( 1st ` <. ( ( 1st ` G ) o. ( 1st ` I ) ) , ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) >. ) ) | 
						
							| 22 |  | fvex |  |-  ( 1st ` I ) e. _V | 
						
							| 23 | 13 22 | coex |  |-  ( ( 1st ` G ) o. ( 1st ` I ) ) e. _V | 
						
							| 24 |  | ovex |  |-  ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) e. _V | 
						
							| 25 | 23 24 | op1st |  |-  ( 1st ` <. ( ( 1st ` G ) o. ( 1st ` I ) ) , ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) >. ) = ( ( 1st ` G ) o. ( 1st ` I ) ) | 
						
							| 26 | 21 25 | eqtrdi |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( 1st ` ( G .+ I ) ) = ( ( 1st ` G ) o. ( 1st ` I ) ) ) | 
						
							| 27 | 26 | coeq2d |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( ( 1st ` F ) o. ( 1st ` ( G .+ I ) ) ) = ( ( 1st ` F ) o. ( ( 1st ` G ) o. ( 1st ` I ) ) ) ) | 
						
							| 28 | 8 18 27 | 3eqtr4a |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( ( 1st ` ( F .+ G ) ) o. ( 1st ` I ) ) = ( ( 1st ` F ) o. ( 1st ` ( G .+ I ) ) ) ) | 
						
							| 29 |  | xp2nd |  |-  ( F e. ( T X. E ) -> ( 2nd ` F ) e. E ) | 
						
							| 30 |  | xp2nd |  |-  ( G e. ( T X. E ) -> ( 2nd ` G ) e. E ) | 
						
							| 31 |  | xp2nd |  |-  ( I e. ( T X. E ) -> ( 2nd ` I ) e. E ) | 
						
							| 32 | 29 30 31 | 3anim123i |  |-  ( ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) -> ( ( 2nd ` F ) e. E /\ ( 2nd ` G ) e. E /\ ( 2nd ` I ) e. E ) ) | 
						
							| 33 |  | eqid |  |-  ( ( EDRing ` K ) ` W ) = ( ( EDRing ` K ) ` W ) | 
						
							| 34 | 1 33 4 5 | dvhsca |  |-  ( ( K e. HL /\ W e. H ) -> D = ( ( EDRing ` K ) ` W ) ) | 
						
							| 35 | 1 33 | erngdv |  |-  ( ( K e. HL /\ W e. H ) -> ( ( EDRing ` K ) ` W ) e. DivRing ) | 
						
							| 36 | 34 35 | eqeltrd |  |-  ( ( K e. HL /\ W e. H ) -> D e. DivRing ) | 
						
							| 37 |  | drnggrp |  |-  ( D e. DivRing -> D e. Grp ) | 
						
							| 38 | 36 37 | syl |  |-  ( ( K e. HL /\ W e. H ) -> D e. Grp ) | 
						
							| 39 | 38 | adantr |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( ( 2nd ` F ) e. E /\ ( 2nd ` G ) e. E /\ ( 2nd ` I ) e. E ) ) -> D e. Grp ) | 
						
							| 40 |  | simpr1 |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( ( 2nd ` F ) e. E /\ ( 2nd ` G ) e. E /\ ( 2nd ` I ) e. E ) ) -> ( 2nd ` F ) e. E ) | 
						
							| 41 |  | eqid |  |-  ( Base ` D ) = ( Base ` D ) | 
						
							| 42 | 1 3 4 5 41 | dvhbase |  |-  ( ( K e. HL /\ W e. H ) -> ( Base ` D ) = E ) | 
						
							| 43 | 42 | adantr |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( ( 2nd ` F ) e. E /\ ( 2nd ` G ) e. E /\ ( 2nd ` I ) e. E ) ) -> ( Base ` D ) = E ) | 
						
							| 44 | 40 43 | eleqtrrd |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( ( 2nd ` F ) e. E /\ ( 2nd ` G ) e. E /\ ( 2nd ` I ) e. E ) ) -> ( 2nd ` F ) e. ( Base ` D ) ) | 
						
							| 45 |  | simpr2 |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( ( 2nd ` F ) e. E /\ ( 2nd ` G ) e. E /\ ( 2nd ` I ) e. E ) ) -> ( 2nd ` G ) e. E ) | 
						
							| 46 | 45 43 | eleqtrrd |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( ( 2nd ` F ) e. E /\ ( 2nd ` G ) e. E /\ ( 2nd ` I ) e. E ) ) -> ( 2nd ` G ) e. ( Base ` D ) ) | 
						
							| 47 |  | simpr3 |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( ( 2nd ` F ) e. E /\ ( 2nd ` G ) e. E /\ ( 2nd ` I ) e. E ) ) -> ( 2nd ` I ) e. E ) | 
						
							| 48 | 47 43 | eleqtrrd |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( ( 2nd ` F ) e. E /\ ( 2nd ` G ) e. E /\ ( 2nd ` I ) e. E ) ) -> ( 2nd ` I ) e. ( Base ` D ) ) | 
						
							| 49 | 41 6 | grpass |  |-  ( ( D e. Grp /\ ( ( 2nd ` F ) e. ( Base ` D ) /\ ( 2nd ` G ) e. ( Base ` D ) /\ ( 2nd ` I ) e. ( Base ` D ) ) ) -> ( ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) .+^ ( 2nd ` I ) ) = ( ( 2nd ` F ) .+^ ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) ) ) | 
						
							| 50 | 39 44 46 48 49 | syl13anc |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( ( 2nd ` F ) e. E /\ ( 2nd ` G ) e. E /\ ( 2nd ` I ) e. E ) ) -> ( ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) .+^ ( 2nd ` I ) ) = ( ( 2nd ` F ) .+^ ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) ) ) | 
						
							| 51 | 32 50 | sylan2 |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) .+^ ( 2nd ` I ) ) = ( ( 2nd ` F ) .+^ ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) ) ) | 
						
							| 52 | 10 | fveq2d |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( 2nd ` ( F .+ G ) ) = ( 2nd ` <. ( ( 1st ` F ) o. ( 1st ` G ) ) , ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) >. ) ) | 
						
							| 53 | 14 15 | op2nd |  |-  ( 2nd ` <. ( ( 1st ` F ) o. ( 1st ` G ) ) , ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) >. ) = ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) | 
						
							| 54 | 52 53 | eqtrdi |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( 2nd ` ( F .+ G ) ) = ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) ) | 
						
							| 55 | 54 | oveq1d |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( ( 2nd ` ( F .+ G ) ) .+^ ( 2nd ` I ) ) = ( ( ( 2nd ` F ) .+^ ( 2nd ` G ) ) .+^ ( 2nd ` I ) ) ) | 
						
							| 56 | 20 | fveq2d |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( 2nd ` ( G .+ I ) ) = ( 2nd ` <. ( ( 1st ` G ) o. ( 1st ` I ) ) , ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) >. ) ) | 
						
							| 57 | 23 24 | op2nd |  |-  ( 2nd ` <. ( ( 1st ` G ) o. ( 1st ` I ) ) , ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) >. ) = ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) | 
						
							| 58 | 56 57 | eqtrdi |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( 2nd ` ( G .+ I ) ) = ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) ) | 
						
							| 59 | 58 | oveq2d |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( ( 2nd ` F ) .+^ ( 2nd ` ( G .+ I ) ) ) = ( ( 2nd ` F ) .+^ ( ( 2nd ` G ) .+^ ( 2nd ` I ) ) ) ) | 
						
							| 60 | 51 55 59 | 3eqtr4d |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( ( 2nd ` ( F .+ G ) ) .+^ ( 2nd ` I ) ) = ( ( 2nd ` F ) .+^ ( 2nd ` ( G .+ I ) ) ) ) | 
						
							| 61 | 28 60 | opeq12d |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> <. ( ( 1st ` ( F .+ G ) ) o. ( 1st ` I ) ) , ( ( 2nd ` ( F .+ G ) ) .+^ ( 2nd ` I ) ) >. = <. ( ( 1st ` F ) o. ( 1st ` ( G .+ I ) ) ) , ( ( 2nd ` F ) .+^ ( 2nd ` ( G .+ I ) ) ) >. ) | 
						
							| 62 |  | simpl |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( K e. HL /\ W e. H ) ) | 
						
							| 63 | 1 2 3 4 5 6 7 | dvhvaddcl |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) ) ) -> ( F .+ G ) e. ( T X. E ) ) | 
						
							| 64 | 63 | 3adantr3 |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( F .+ G ) e. ( T X. E ) ) | 
						
							| 65 |  | simpr3 |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> I e. ( T X. E ) ) | 
						
							| 66 | 1 2 3 4 5 7 6 | dvhvadd |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( ( F .+ G ) e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( ( F .+ G ) .+ I ) = <. ( ( 1st ` ( F .+ G ) ) o. ( 1st ` I ) ) , ( ( 2nd ` ( F .+ G ) ) .+^ ( 2nd ` I ) ) >. ) | 
						
							| 67 | 62 64 65 66 | syl12anc |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( ( F .+ G ) .+ I ) = <. ( ( 1st ` ( F .+ G ) ) o. ( 1st ` I ) ) , ( ( 2nd ` ( F .+ G ) ) .+^ ( 2nd ` I ) ) >. ) | 
						
							| 68 |  | simpr1 |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> F e. ( T X. E ) ) | 
						
							| 69 | 1 2 3 4 5 6 7 | dvhvaddcl |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( G .+ I ) e. ( T X. E ) ) | 
						
							| 70 | 69 | 3adantr1 |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( G .+ I ) e. ( T X. E ) ) | 
						
							| 71 | 1 2 3 4 5 7 6 | dvhvadd |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ ( G .+ I ) e. ( T X. E ) ) ) -> ( F .+ ( G .+ I ) ) = <. ( ( 1st ` F ) o. ( 1st ` ( G .+ I ) ) ) , ( ( 2nd ` F ) .+^ ( 2nd ` ( G .+ I ) ) ) >. ) | 
						
							| 72 | 62 68 70 71 | syl12anc |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( F .+ ( G .+ I ) ) = <. ( ( 1st ` F ) o. ( 1st ` ( G .+ I ) ) ) , ( ( 2nd ` F ) .+^ ( 2nd ` ( G .+ I ) ) ) >. ) | 
						
							| 73 | 61 67 72 | 3eqtr4d |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( F e. ( T X. E ) /\ G e. ( T X. E ) /\ I e. ( T X. E ) ) ) -> ( ( F .+ G ) .+ I ) = ( F .+ ( G .+ I ) ) ) |