| Step | Hyp | Ref | Expression | 
						
							| 1 |  | gsumzunsnd.b |  |-  B = ( Base ` G ) | 
						
							| 2 |  | gsumzunsnd.p |  |-  .+ = ( +g ` G ) | 
						
							| 3 |  | gsumzunsnd.z |  |-  Z = ( Cntz ` G ) | 
						
							| 4 |  | gsumzunsnd.f |  |-  F = ( k e. ( A u. { M } ) |-> X ) | 
						
							| 5 |  | gsumzunsnd.g |  |-  ( ph -> G e. Mnd ) | 
						
							| 6 |  | gsumzunsnd.a |  |-  ( ph -> A e. Fin ) | 
						
							| 7 |  | gsumzunsnd.c |  |-  ( ph -> ran F C_ ( Z ` ran F ) ) | 
						
							| 8 |  | gsumzunsnd.x |  |-  ( ( ph /\ k e. A ) -> X e. B ) | 
						
							| 9 |  | gsumzunsnd.m |  |-  ( ph -> M e. V ) | 
						
							| 10 |  | gsumzunsnd.d |  |-  ( ph -> -. M e. A ) | 
						
							| 11 |  | gsumzunsnd.y |  |-  ( ph -> Y e. B ) | 
						
							| 12 |  | gsumzunsnd.s |  |-  ( ( ph /\ k = M ) -> X = Y ) | 
						
							| 13 |  | eqid |  |-  ( 0g ` G ) = ( 0g ` G ) | 
						
							| 14 |  | snfi |  |-  { M } e. Fin | 
						
							| 15 |  | unfi |  |-  ( ( A e. Fin /\ { M } e. Fin ) -> ( A u. { M } ) e. Fin ) | 
						
							| 16 | 6 14 15 | sylancl |  |-  ( ph -> ( A u. { M } ) e. Fin ) | 
						
							| 17 |  | elun |  |-  ( k e. ( A u. { M } ) <-> ( k e. A \/ k e. { M } ) ) | 
						
							| 18 |  | elsni |  |-  ( k e. { M } -> k = M ) | 
						
							| 19 | 18 12 | sylan2 |  |-  ( ( ph /\ k e. { M } ) -> X = Y ) | 
						
							| 20 | 11 | adantr |  |-  ( ( ph /\ k e. { M } ) -> Y e. B ) | 
						
							| 21 | 19 20 | eqeltrd |  |-  ( ( ph /\ k e. { M } ) -> X e. B ) | 
						
							| 22 | 8 21 | jaodan |  |-  ( ( ph /\ ( k e. A \/ k e. { M } ) ) -> X e. B ) | 
						
							| 23 | 17 22 | sylan2b |  |-  ( ( ph /\ k e. ( A u. { M } ) ) -> X e. B ) | 
						
							| 24 | 23 4 | fmptd |  |-  ( ph -> F : ( A u. { M } ) --> B ) | 
						
							| 25 | 8 | expcom |  |-  ( k e. A -> ( ph -> X e. B ) ) | 
						
							| 26 | 11 | adantr |  |-  ( ( ph /\ k = M ) -> Y e. B ) | 
						
							| 27 | 12 26 | eqeltrd |  |-  ( ( ph /\ k = M ) -> X e. B ) | 
						
							| 28 | 27 | expcom |  |-  ( k = M -> ( ph -> X e. B ) ) | 
						
							| 29 | 18 28 | syl |  |-  ( k e. { M } -> ( ph -> X e. B ) ) | 
						
							| 30 | 25 29 | jaoi |  |-  ( ( k e. A \/ k e. { M } ) -> ( ph -> X e. B ) ) | 
						
							| 31 | 17 30 | sylbi |  |-  ( k e. ( A u. { M } ) -> ( ph -> X e. B ) ) | 
						
							| 32 | 31 | impcom |  |-  ( ( ph /\ k e. ( A u. { M } ) ) -> X e. B ) | 
						
							| 33 |  | fvexd |  |-  ( ph -> ( 0g ` G ) e. _V ) | 
						
							| 34 | 4 16 32 33 | fsuppmptdm |  |-  ( ph -> F finSupp ( 0g ` G ) ) | 
						
							| 35 |  | disjsn |  |-  ( ( A i^i { M } ) = (/) <-> -. M e. A ) | 
						
							| 36 | 10 35 | sylibr |  |-  ( ph -> ( A i^i { M } ) = (/) ) | 
						
							| 37 |  | eqidd |  |-  ( ph -> ( A u. { M } ) = ( A u. { M } ) ) | 
						
							| 38 | 1 13 2 3 5 16 24 7 34 36 37 | gsumzsplit |  |-  ( ph -> ( G gsum F ) = ( ( G gsum ( F |` A ) ) .+ ( G gsum ( F |` { M } ) ) ) ) | 
						
							| 39 | 4 | reseq1i |  |-  ( F |` A ) = ( ( k e. ( A u. { M } ) |-> X ) |` A ) | 
						
							| 40 |  | ssun1 |  |-  A C_ ( A u. { M } ) | 
						
							| 41 |  | resmpt |  |-  ( A C_ ( A u. { M } ) -> ( ( k e. ( A u. { M } ) |-> X ) |` A ) = ( k e. A |-> X ) ) | 
						
							| 42 | 40 41 | mp1i |  |-  ( ph -> ( ( k e. ( A u. { M } ) |-> X ) |` A ) = ( k e. A |-> X ) ) | 
						
							| 43 | 39 42 | eqtrid |  |-  ( ph -> ( F |` A ) = ( k e. A |-> X ) ) | 
						
							| 44 | 43 | oveq2d |  |-  ( ph -> ( G gsum ( F |` A ) ) = ( G gsum ( k e. A |-> X ) ) ) | 
						
							| 45 | 4 | reseq1i |  |-  ( F |` { M } ) = ( ( k e. ( A u. { M } ) |-> X ) |` { M } ) | 
						
							| 46 |  | ssun2 |  |-  { M } C_ ( A u. { M } ) | 
						
							| 47 |  | resmpt |  |-  ( { M } C_ ( A u. { M } ) -> ( ( k e. ( A u. { M } ) |-> X ) |` { M } ) = ( k e. { M } |-> X ) ) | 
						
							| 48 | 46 47 | mp1i |  |-  ( ph -> ( ( k e. ( A u. { M } ) |-> X ) |` { M } ) = ( k e. { M } |-> X ) ) | 
						
							| 49 | 45 48 | eqtrid |  |-  ( ph -> ( F |` { M } ) = ( k e. { M } |-> X ) ) | 
						
							| 50 | 49 | oveq2d |  |-  ( ph -> ( G gsum ( F |` { M } ) ) = ( G gsum ( k e. { M } |-> X ) ) ) | 
						
							| 51 | 44 50 | oveq12d |  |-  ( ph -> ( ( G gsum ( F |` A ) ) .+ ( G gsum ( F |` { M } ) ) ) = ( ( G gsum ( k e. A |-> X ) ) .+ ( G gsum ( k e. { M } |-> X ) ) ) ) | 
						
							| 52 | 1 5 9 11 12 | gsumsnd |  |-  ( ph -> ( G gsum ( k e. { M } |-> X ) ) = Y ) | 
						
							| 53 | 52 | oveq2d |  |-  ( ph -> ( ( G gsum ( k e. A |-> X ) ) .+ ( G gsum ( k e. { M } |-> X ) ) ) = ( ( G gsum ( k e. A |-> X ) ) .+ Y ) ) | 
						
							| 54 | 38 51 53 | 3eqtrd |  |-  ( ph -> ( G gsum F ) = ( ( G gsum ( k e. A |-> X ) ) .+ Y ) ) |