| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lactghmga.x | ⊢ 𝑋  =  ( Base ‘ 𝐺 ) | 
						
							| 2 |  | lactghmga.h | ⊢ 𝐻  =  ( SymGrp ‘ 𝑌 ) | 
						
							| 3 |  | lactghmga.f | ⊢  ⊕   =  ( 𝑥  ∈  𝑋 ,  𝑦  ∈  𝑌  ↦  ( ( 𝐹 ‘ 𝑥 ) ‘ 𝑦 ) ) | 
						
							| 4 |  | ghmgrp1 | ⊢ ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  →  𝐺  ∈  Grp ) | 
						
							| 5 |  | ghmgrp2 | ⊢ ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  →  𝐻  ∈  Grp ) | 
						
							| 6 |  | grpn0 | ⊢ ( 𝐻  ∈  Grp  →  𝐻  ≠  ∅ ) | 
						
							| 7 |  | fvprc | ⊢ ( ¬  𝑌  ∈  V  →  ( SymGrp ‘ 𝑌 )  =  ∅ ) | 
						
							| 8 | 2 7 | eqtrid | ⊢ ( ¬  𝑌  ∈  V  →  𝐻  =  ∅ ) | 
						
							| 9 | 8 | necon1ai | ⊢ ( 𝐻  ≠  ∅  →  𝑌  ∈  V ) | 
						
							| 10 | 5 6 9 | 3syl | ⊢ ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  →  𝑌  ∈  V ) | 
						
							| 11 |  | eqid | ⊢ ( Base ‘ 𝐻 )  =  ( Base ‘ 𝐻 ) | 
						
							| 12 | 1 11 | ghmf | ⊢ ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  →  𝐹 : 𝑋 ⟶ ( Base ‘ 𝐻 ) ) | 
						
							| 13 | 12 | ffvelcdmda | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑥  ∈  𝑋 )  →  ( 𝐹 ‘ 𝑥 )  ∈  ( Base ‘ 𝐻 ) ) | 
						
							| 14 | 10 | adantr | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑥  ∈  𝑋 )  →  𝑌  ∈  V ) | 
						
							| 15 | 2 11 | elsymgbas | ⊢ ( 𝑌  ∈  V  →  ( ( 𝐹 ‘ 𝑥 )  ∈  ( Base ‘ 𝐻 )  ↔  ( 𝐹 ‘ 𝑥 ) : 𝑌 –1-1-onto→ 𝑌 ) ) | 
						
							| 16 | 14 15 | syl | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑥  ∈  𝑋 )  →  ( ( 𝐹 ‘ 𝑥 )  ∈  ( Base ‘ 𝐻 )  ↔  ( 𝐹 ‘ 𝑥 ) : 𝑌 –1-1-onto→ 𝑌 ) ) | 
						
							| 17 | 13 16 | mpbid | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑥  ∈  𝑋 )  →  ( 𝐹 ‘ 𝑥 ) : 𝑌 –1-1-onto→ 𝑌 ) | 
						
							| 18 |  | f1of | ⊢ ( ( 𝐹 ‘ 𝑥 ) : 𝑌 –1-1-onto→ 𝑌  →  ( 𝐹 ‘ 𝑥 ) : 𝑌 ⟶ 𝑌 ) | 
						
							| 19 | 17 18 | syl | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑥  ∈  𝑋 )  →  ( 𝐹 ‘ 𝑥 ) : 𝑌 ⟶ 𝑌 ) | 
						
							| 20 | 19 | ffvelcdmda | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑥  ∈  𝑋 )  ∧  𝑦  ∈  𝑌 )  →  ( ( 𝐹 ‘ 𝑥 ) ‘ 𝑦 )  ∈  𝑌 ) | 
						
							| 21 | 20 | ralrimiva | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑥  ∈  𝑋 )  →  ∀ 𝑦  ∈  𝑌 ( ( 𝐹 ‘ 𝑥 ) ‘ 𝑦 )  ∈  𝑌 ) | 
						
							| 22 | 21 | ralrimiva | ⊢ ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  →  ∀ 𝑥  ∈  𝑋 ∀ 𝑦  ∈  𝑌 ( ( 𝐹 ‘ 𝑥 ) ‘ 𝑦 )  ∈  𝑌 ) | 
						
							| 23 | 3 | fmpo | ⊢ ( ∀ 𝑥  ∈  𝑋 ∀ 𝑦  ∈  𝑌 ( ( 𝐹 ‘ 𝑥 ) ‘ 𝑦 )  ∈  𝑌  ↔   ⊕  : ( 𝑋  ×  𝑌 ) ⟶ 𝑌 ) | 
						
							| 24 | 22 23 | sylib | ⊢ ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  →   ⊕  : ( 𝑋  ×  𝑌 ) ⟶ 𝑌 ) | 
						
							| 25 |  | eqid | ⊢ ( 0g ‘ 𝐺 )  =  ( 0g ‘ 𝐺 ) | 
						
							| 26 | 1 25 | grpidcl | ⊢ ( 𝐺  ∈  Grp  →  ( 0g ‘ 𝐺 )  ∈  𝑋 ) | 
						
							| 27 | 4 26 | syl | ⊢ ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  →  ( 0g ‘ 𝐺 )  ∈  𝑋 ) | 
						
							| 28 |  | fveq2 | ⊢ ( 𝑥  =  ( 0g ‘ 𝐺 )  →  ( 𝐹 ‘ 𝑥 )  =  ( 𝐹 ‘ ( 0g ‘ 𝐺 ) ) ) | 
						
							| 29 | 28 | fveq1d | ⊢ ( 𝑥  =  ( 0g ‘ 𝐺 )  →  ( ( 𝐹 ‘ 𝑥 ) ‘ 𝑦 )  =  ( ( 𝐹 ‘ ( 0g ‘ 𝐺 ) ) ‘ 𝑦 ) ) | 
						
							| 30 |  | fveq2 | ⊢ ( 𝑦  =  𝑧  →  ( ( 𝐹 ‘ ( 0g ‘ 𝐺 ) ) ‘ 𝑦 )  =  ( ( 𝐹 ‘ ( 0g ‘ 𝐺 ) ) ‘ 𝑧 ) ) | 
						
							| 31 |  | fvex | ⊢ ( ( 𝐹 ‘ ( 0g ‘ 𝐺 ) ) ‘ 𝑧 )  ∈  V | 
						
							| 32 | 29 30 3 31 | ovmpo | ⊢ ( ( ( 0g ‘ 𝐺 )  ∈  𝑋  ∧  𝑧  ∈  𝑌 )  →  ( ( 0g ‘ 𝐺 )  ⊕  𝑧 )  =  ( ( 𝐹 ‘ ( 0g ‘ 𝐺 ) ) ‘ 𝑧 ) ) | 
						
							| 33 | 27 32 | sylan | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  →  ( ( 0g ‘ 𝐺 )  ⊕  𝑧 )  =  ( ( 𝐹 ‘ ( 0g ‘ 𝐺 ) ) ‘ 𝑧 ) ) | 
						
							| 34 |  | eqid | ⊢ ( 0g ‘ 𝐻 )  =  ( 0g ‘ 𝐻 ) | 
						
							| 35 | 25 34 | ghmid | ⊢ ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  →  ( 𝐹 ‘ ( 0g ‘ 𝐺 ) )  =  ( 0g ‘ 𝐻 ) ) | 
						
							| 36 | 35 | adantr | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  →  ( 𝐹 ‘ ( 0g ‘ 𝐺 ) )  =  ( 0g ‘ 𝐻 ) ) | 
						
							| 37 | 10 | adantr | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  →  𝑌  ∈  V ) | 
						
							| 38 | 2 | symgid | ⊢ ( 𝑌  ∈  V  →  (  I   ↾  𝑌 )  =  ( 0g ‘ 𝐻 ) ) | 
						
							| 39 | 37 38 | syl | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  →  (  I   ↾  𝑌 )  =  ( 0g ‘ 𝐻 ) ) | 
						
							| 40 | 36 39 | eqtr4d | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  →  ( 𝐹 ‘ ( 0g ‘ 𝐺 ) )  =  (  I   ↾  𝑌 ) ) | 
						
							| 41 | 40 | fveq1d | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  →  ( ( 𝐹 ‘ ( 0g ‘ 𝐺 ) ) ‘ 𝑧 )  =  ( (  I   ↾  𝑌 ) ‘ 𝑧 ) ) | 
						
							| 42 |  | fvresi | ⊢ ( 𝑧  ∈  𝑌  →  ( (  I   ↾  𝑌 ) ‘ 𝑧 )  =  𝑧 ) | 
						
							| 43 | 42 | adantl | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  →  ( (  I   ↾  𝑌 ) ‘ 𝑧 )  =  𝑧 ) | 
						
							| 44 | 33 41 43 | 3eqtrd | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  →  ( ( 0g ‘ 𝐺 )  ⊕  𝑧 )  =  𝑧 ) | 
						
							| 45 | 12 | ad2antrr | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  𝐹 : 𝑋 ⟶ ( Base ‘ 𝐻 ) ) | 
						
							| 46 |  | simprr | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  𝑣  ∈  𝑋 ) | 
						
							| 47 | 45 46 | ffvelcdmd | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( 𝐹 ‘ 𝑣 )  ∈  ( Base ‘ 𝐻 ) ) | 
						
							| 48 | 10 | ad2antrr | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  𝑌  ∈  V ) | 
						
							| 49 | 2 11 | elsymgbas | ⊢ ( 𝑌  ∈  V  →  ( ( 𝐹 ‘ 𝑣 )  ∈  ( Base ‘ 𝐻 )  ↔  ( 𝐹 ‘ 𝑣 ) : 𝑌 –1-1-onto→ 𝑌 ) ) | 
						
							| 50 | 48 49 | syl | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( ( 𝐹 ‘ 𝑣 )  ∈  ( Base ‘ 𝐻 )  ↔  ( 𝐹 ‘ 𝑣 ) : 𝑌 –1-1-onto→ 𝑌 ) ) | 
						
							| 51 | 47 50 | mpbid | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( 𝐹 ‘ 𝑣 ) : 𝑌 –1-1-onto→ 𝑌 ) | 
						
							| 52 |  | f1of | ⊢ ( ( 𝐹 ‘ 𝑣 ) : 𝑌 –1-1-onto→ 𝑌  →  ( 𝐹 ‘ 𝑣 ) : 𝑌 ⟶ 𝑌 ) | 
						
							| 53 | 51 52 | syl | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( 𝐹 ‘ 𝑣 ) : 𝑌 ⟶ 𝑌 ) | 
						
							| 54 |  | simplr | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  𝑧  ∈  𝑌 ) | 
						
							| 55 |  | fvco3 | ⊢ ( ( ( 𝐹 ‘ 𝑣 ) : 𝑌 ⟶ 𝑌  ∧  𝑧  ∈  𝑌 )  →  ( ( ( 𝐹 ‘ 𝑢 )  ∘  ( 𝐹 ‘ 𝑣 ) ) ‘ 𝑧 )  =  ( ( 𝐹 ‘ 𝑢 ) ‘ ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) ) ) | 
						
							| 56 | 53 54 55 | syl2anc | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( ( ( 𝐹 ‘ 𝑢 )  ∘  ( 𝐹 ‘ 𝑣 ) ) ‘ 𝑧 )  =  ( ( 𝐹 ‘ 𝑢 ) ‘ ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) ) ) | 
						
							| 57 |  | simpll | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  𝐹  ∈  ( 𝐺  GrpHom  𝐻 ) ) | 
						
							| 58 |  | simprl | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  𝑢  ∈  𝑋 ) | 
						
							| 59 |  | eqid | ⊢ ( +g ‘ 𝐺 )  =  ( +g ‘ 𝐺 ) | 
						
							| 60 |  | eqid | ⊢ ( +g ‘ 𝐻 )  =  ( +g ‘ 𝐻 ) | 
						
							| 61 | 1 59 60 | ghmlin | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 )  →  ( 𝐹 ‘ ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 ) )  =  ( ( 𝐹 ‘ 𝑢 ) ( +g ‘ 𝐻 ) ( 𝐹 ‘ 𝑣 ) ) ) | 
						
							| 62 | 57 58 46 61 | syl3anc | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( 𝐹 ‘ ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 ) )  =  ( ( 𝐹 ‘ 𝑢 ) ( +g ‘ 𝐻 ) ( 𝐹 ‘ 𝑣 ) ) ) | 
						
							| 63 | 45 58 | ffvelcdmd | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( 𝐹 ‘ 𝑢 )  ∈  ( Base ‘ 𝐻 ) ) | 
						
							| 64 | 2 11 60 | symgov | ⊢ ( ( ( 𝐹 ‘ 𝑢 )  ∈  ( Base ‘ 𝐻 )  ∧  ( 𝐹 ‘ 𝑣 )  ∈  ( Base ‘ 𝐻 ) )  →  ( ( 𝐹 ‘ 𝑢 ) ( +g ‘ 𝐻 ) ( 𝐹 ‘ 𝑣 ) )  =  ( ( 𝐹 ‘ 𝑢 )  ∘  ( 𝐹 ‘ 𝑣 ) ) ) | 
						
							| 65 | 63 47 64 | syl2anc | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( ( 𝐹 ‘ 𝑢 ) ( +g ‘ 𝐻 ) ( 𝐹 ‘ 𝑣 ) )  =  ( ( 𝐹 ‘ 𝑢 )  ∘  ( 𝐹 ‘ 𝑣 ) ) ) | 
						
							| 66 | 62 65 | eqtrd | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( 𝐹 ‘ ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 ) )  =  ( ( 𝐹 ‘ 𝑢 )  ∘  ( 𝐹 ‘ 𝑣 ) ) ) | 
						
							| 67 | 66 | fveq1d | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( ( 𝐹 ‘ ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 ) ) ‘ 𝑧 )  =  ( ( ( 𝐹 ‘ 𝑢 )  ∘  ( 𝐹 ‘ 𝑣 ) ) ‘ 𝑧 ) ) | 
						
							| 68 | 53 54 | ffvelcdmd | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 )  ∈  𝑌 ) | 
						
							| 69 |  | fveq2 | ⊢ ( 𝑥  =  𝑢  →  ( 𝐹 ‘ 𝑥 )  =  ( 𝐹 ‘ 𝑢 ) ) | 
						
							| 70 | 69 | fveq1d | ⊢ ( 𝑥  =  𝑢  →  ( ( 𝐹 ‘ 𝑥 ) ‘ 𝑦 )  =  ( ( 𝐹 ‘ 𝑢 ) ‘ 𝑦 ) ) | 
						
							| 71 |  | fveq2 | ⊢ ( 𝑦  =  ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 )  →  ( ( 𝐹 ‘ 𝑢 ) ‘ 𝑦 )  =  ( ( 𝐹 ‘ 𝑢 ) ‘ ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) ) ) | 
						
							| 72 |  | fvex | ⊢ ( ( 𝐹 ‘ 𝑢 ) ‘ ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) )  ∈  V | 
						
							| 73 | 70 71 3 72 | ovmpo | ⊢ ( ( 𝑢  ∈  𝑋  ∧  ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 )  ∈  𝑌 )  →  ( 𝑢  ⊕  ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) )  =  ( ( 𝐹 ‘ 𝑢 ) ‘ ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) ) ) | 
						
							| 74 | 58 68 73 | syl2anc | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( 𝑢  ⊕  ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) )  =  ( ( 𝐹 ‘ 𝑢 ) ‘ ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) ) ) | 
						
							| 75 | 56 67 74 | 3eqtr4d | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( ( 𝐹 ‘ ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 ) ) ‘ 𝑧 )  =  ( 𝑢  ⊕  ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) ) ) | 
						
							| 76 | 4 | ad2antrr | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  𝐺  ∈  Grp ) | 
						
							| 77 | 1 59 | grpcl | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 )  →  ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  ∈  𝑋 ) | 
						
							| 78 | 76 58 46 77 | syl3anc | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  ∈  𝑋 ) | 
						
							| 79 |  | fveq2 | ⊢ ( 𝑥  =  ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  →  ( 𝐹 ‘ 𝑥 )  =  ( 𝐹 ‘ ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 ) ) ) | 
						
							| 80 | 79 | fveq1d | ⊢ ( 𝑥  =  ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  →  ( ( 𝐹 ‘ 𝑥 ) ‘ 𝑦 )  =  ( ( 𝐹 ‘ ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 ) ) ‘ 𝑦 ) ) | 
						
							| 81 |  | fveq2 | ⊢ ( 𝑦  =  𝑧  →  ( ( 𝐹 ‘ ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 ) ) ‘ 𝑦 )  =  ( ( 𝐹 ‘ ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 ) ) ‘ 𝑧 ) ) | 
						
							| 82 |  | fvex | ⊢ ( ( 𝐹 ‘ ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 ) ) ‘ 𝑧 )  ∈  V | 
						
							| 83 | 80 81 3 82 | ovmpo | ⊢ ( ( ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  ∈  𝑋  ∧  𝑧  ∈  𝑌 )  →  ( ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  ⊕  𝑧 )  =  ( ( 𝐹 ‘ ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 ) ) ‘ 𝑧 ) ) | 
						
							| 84 | 78 54 83 | syl2anc | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  ⊕  𝑧 )  =  ( ( 𝐹 ‘ ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 ) ) ‘ 𝑧 ) ) | 
						
							| 85 |  | fveq2 | ⊢ ( 𝑥  =  𝑣  →  ( 𝐹 ‘ 𝑥 )  =  ( 𝐹 ‘ 𝑣 ) ) | 
						
							| 86 | 85 | fveq1d | ⊢ ( 𝑥  =  𝑣  →  ( ( 𝐹 ‘ 𝑥 ) ‘ 𝑦 )  =  ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑦 ) ) | 
						
							| 87 |  | fveq2 | ⊢ ( 𝑦  =  𝑧  →  ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑦 )  =  ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) ) | 
						
							| 88 |  | fvex | ⊢ ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 )  ∈  V | 
						
							| 89 | 86 87 3 88 | ovmpo | ⊢ ( ( 𝑣  ∈  𝑋  ∧  𝑧  ∈  𝑌 )  →  ( 𝑣  ⊕  𝑧 )  =  ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) ) | 
						
							| 90 | 46 54 89 | syl2anc | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( 𝑣  ⊕  𝑧 )  =  ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) ) | 
						
							| 91 | 90 | oveq2d | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( 𝑢  ⊕  ( 𝑣  ⊕  𝑧 ) )  =  ( 𝑢  ⊕  ( ( 𝐹 ‘ 𝑣 ) ‘ 𝑧 ) ) ) | 
						
							| 92 | 75 84 91 | 3eqtr4d | ⊢ ( ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  ∧  ( 𝑢  ∈  𝑋  ∧  𝑣  ∈  𝑋 ) )  →  ( ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  ⊕  𝑧 )  =  ( 𝑢  ⊕  ( 𝑣  ⊕  𝑧 ) ) ) | 
						
							| 93 | 92 | ralrimivva | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  →  ∀ 𝑢  ∈  𝑋 ∀ 𝑣  ∈  𝑋 ( ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  ⊕  𝑧 )  =  ( 𝑢  ⊕  ( 𝑣  ⊕  𝑧 ) ) ) | 
						
							| 94 | 44 93 | jca | ⊢ ( ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  ∧  𝑧  ∈  𝑌 )  →  ( ( ( 0g ‘ 𝐺 )  ⊕  𝑧 )  =  𝑧  ∧  ∀ 𝑢  ∈  𝑋 ∀ 𝑣  ∈  𝑋 ( ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  ⊕  𝑧 )  =  ( 𝑢  ⊕  ( 𝑣  ⊕  𝑧 ) ) ) ) | 
						
							| 95 | 94 | ralrimiva | ⊢ ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  →  ∀ 𝑧  ∈  𝑌 ( ( ( 0g ‘ 𝐺 )  ⊕  𝑧 )  =  𝑧  ∧  ∀ 𝑢  ∈  𝑋 ∀ 𝑣  ∈  𝑋 ( ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  ⊕  𝑧 )  =  ( 𝑢  ⊕  ( 𝑣  ⊕  𝑧 ) ) ) ) | 
						
							| 96 | 24 95 | jca | ⊢ ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  →  (  ⊕  : ( 𝑋  ×  𝑌 ) ⟶ 𝑌  ∧  ∀ 𝑧  ∈  𝑌 ( ( ( 0g ‘ 𝐺 )  ⊕  𝑧 )  =  𝑧  ∧  ∀ 𝑢  ∈  𝑋 ∀ 𝑣  ∈  𝑋 ( ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  ⊕  𝑧 )  =  ( 𝑢  ⊕  ( 𝑣  ⊕  𝑧 ) ) ) ) ) | 
						
							| 97 | 1 59 25 | isga | ⊢ (  ⊕   ∈  ( 𝐺  GrpAct  𝑌 )  ↔  ( ( 𝐺  ∈  Grp  ∧  𝑌  ∈  V )  ∧  (  ⊕  : ( 𝑋  ×  𝑌 ) ⟶ 𝑌  ∧  ∀ 𝑧  ∈  𝑌 ( ( ( 0g ‘ 𝐺 )  ⊕  𝑧 )  =  𝑧  ∧  ∀ 𝑢  ∈  𝑋 ∀ 𝑣  ∈  𝑋 ( ( 𝑢 ( +g ‘ 𝐺 ) 𝑣 )  ⊕  𝑧 )  =  ( 𝑢  ⊕  ( 𝑣  ⊕  𝑧 ) ) ) ) ) ) | 
						
							| 98 | 4 10 96 97 | syl21anbrc | ⊢ ( 𝐹  ∈  ( 𝐺  GrpHom  𝐻 )  →   ⊕   ∈  ( 𝐺  GrpAct  𝑌 ) ) |