| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mat1rhmval.k | ⊢ 𝐾  =  ( Base ‘ 𝑅 ) | 
						
							| 2 |  | mat1rhmval.a | ⊢ 𝐴  =  ( { 𝐸 }  Mat  𝑅 ) | 
						
							| 3 |  | mat1rhmval.b | ⊢ 𝐵  =  ( Base ‘ 𝐴 ) | 
						
							| 4 |  | mat1rhmval.o | ⊢ 𝑂  =  〈 𝐸 ,  𝐸 〉 | 
						
							| 5 |  | mat1rhmval.f | ⊢ 𝐹  =  ( 𝑥  ∈  𝐾  ↦  { 〈 𝑂 ,  𝑥 〉 } ) | 
						
							| 6 |  | eqid | ⊢ ( +g ‘ 𝑅 )  =  ( +g ‘ 𝑅 ) | 
						
							| 7 |  | eqid | ⊢ ( +g ‘ 𝐴 )  =  ( +g ‘ 𝐴 ) | 
						
							| 8 |  | ringgrp | ⊢ ( 𝑅  ∈  Ring  →  𝑅  ∈  Grp ) | 
						
							| 9 | 8 | adantr | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  →  𝑅  ∈  Grp ) | 
						
							| 10 |  | snfi | ⊢ { 𝐸 }  ∈  Fin | 
						
							| 11 |  | simpl | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  →  𝑅  ∈  Ring ) | 
						
							| 12 | 2 | matgrp | ⊢ ( ( { 𝐸 }  ∈  Fin  ∧  𝑅  ∈  Ring )  →  𝐴  ∈  Grp ) | 
						
							| 13 | 10 11 12 | sylancr | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  →  𝐴  ∈  Grp ) | 
						
							| 14 | 1 2 3 4 5 | mat1f | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  →  𝐹 : 𝐾 ⟶ 𝐵 ) | 
						
							| 15 | 11 | adantr | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  𝑅  ∈  Ring ) | 
						
							| 16 |  | simpr | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  →  𝐸  ∈  𝑉 ) | 
						
							| 17 | 16 | adantr | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  𝐸  ∈  𝑉 ) | 
						
							| 18 |  | simpl | ⊢ ( ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 )  →  𝑤  ∈  𝐾 ) | 
						
							| 19 | 18 | adantl | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  𝑤  ∈  𝐾 ) | 
						
							| 20 | 1 2 3 4 5 | mat1rhmelval | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉  ∧  𝑤  ∈  𝐾 )  →  ( 𝐸 ( 𝐹 ‘ 𝑤 ) 𝐸 )  =  𝑤 ) | 
						
							| 21 | 15 17 19 20 | syl3anc | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( 𝐸 ( 𝐹 ‘ 𝑤 ) 𝐸 )  =  𝑤 ) | 
						
							| 22 |  | simpr | ⊢ ( ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 )  →  𝑦  ∈  𝐾 ) | 
						
							| 23 | 22 | adantl | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  𝑦  ∈  𝐾 ) | 
						
							| 24 | 1 2 3 4 5 | mat1rhmelval | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉  ∧  𝑦  ∈  𝐾 )  →  ( 𝐸 ( 𝐹 ‘ 𝑦 ) 𝐸 )  =  𝑦 ) | 
						
							| 25 | 15 17 23 24 | syl3anc | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( 𝐸 ( 𝐹 ‘ 𝑦 ) 𝐸 )  =  𝑦 ) | 
						
							| 26 | 21 25 | oveq12d | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( ( 𝐸 ( 𝐹 ‘ 𝑤 ) 𝐸 ) ( +g ‘ 𝑅 ) ( 𝐸 ( 𝐹 ‘ 𝑦 ) 𝐸 ) )  =  ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) | 
						
							| 27 | 1 2 3 4 5 | mat1rhmcl | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉  ∧  𝑤  ∈  𝐾 )  →  ( 𝐹 ‘ 𝑤 )  ∈  𝐵 ) | 
						
							| 28 | 15 17 19 27 | syl3anc | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( 𝐹 ‘ 𝑤 )  ∈  𝐵 ) | 
						
							| 29 | 1 2 3 4 5 | mat1rhmcl | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉  ∧  𝑦  ∈  𝐾 )  →  ( 𝐹 ‘ 𝑦 )  ∈  𝐵 ) | 
						
							| 30 | 15 17 23 29 | syl3anc | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( 𝐹 ‘ 𝑦 )  ∈  𝐵 ) | 
						
							| 31 |  | snidg | ⊢ ( 𝐸  ∈  𝑉  →  𝐸  ∈  { 𝐸 } ) | 
						
							| 32 | 31 31 | jca | ⊢ ( 𝐸  ∈  𝑉  →  ( 𝐸  ∈  { 𝐸 }  ∧  𝐸  ∈  { 𝐸 } ) ) | 
						
							| 33 | 32 | adantl | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  →  ( 𝐸  ∈  { 𝐸 }  ∧  𝐸  ∈  { 𝐸 } ) ) | 
						
							| 34 | 33 | adantr | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( 𝐸  ∈  { 𝐸 }  ∧  𝐸  ∈  { 𝐸 } ) ) | 
						
							| 35 | 2 3 7 6 | matplusgcell | ⊢ ( ( ( ( 𝐹 ‘ 𝑤 )  ∈  𝐵  ∧  ( 𝐹 ‘ 𝑦 )  ∈  𝐵 )  ∧  ( 𝐸  ∈  { 𝐸 }  ∧  𝐸  ∈  { 𝐸 } ) )  →  ( 𝐸 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝐸 )  =  ( ( 𝐸 ( 𝐹 ‘ 𝑤 ) 𝐸 ) ( +g ‘ 𝑅 ) ( 𝐸 ( 𝐹 ‘ 𝑦 ) 𝐸 ) ) ) | 
						
							| 36 | 28 30 34 35 | syl21anc | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( 𝐸 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝐸 )  =  ( ( 𝐸 ( 𝐹 ‘ 𝑤 ) 𝐸 ) ( +g ‘ 𝑅 ) ( 𝐸 ( 𝐹 ‘ 𝑦 ) 𝐸 ) ) ) | 
						
							| 37 | 1 6 | ringacl | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 )  →  ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 )  ∈  𝐾 ) | 
						
							| 38 | 15 19 23 37 | syl3anc | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 )  ∈  𝐾 ) | 
						
							| 39 | 1 2 3 4 5 | mat1rhmelval | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉  ∧  ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 )  ∈  𝐾 )  →  ( 𝐸 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝐸 )  =  ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) | 
						
							| 40 | 15 17 38 39 | syl3anc | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( 𝐸 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝐸 )  =  ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) | 
						
							| 41 | 26 36 40 | 3eqtr4rd | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( 𝐸 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝐸 )  =  ( 𝐸 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝐸 ) ) | 
						
							| 42 |  | oveq1 | ⊢ ( 𝑖  =  𝐸  →  ( 𝑖 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝑗 )  =  ( 𝐸 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝑗 ) ) | 
						
							| 43 |  | oveq1 | ⊢ ( 𝑖  =  𝐸  →  ( 𝑖 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝑗 )  =  ( 𝐸 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝑗 ) ) | 
						
							| 44 | 42 43 | eqeq12d | ⊢ ( 𝑖  =  𝐸  →  ( ( 𝑖 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝑗 )  =  ( 𝑖 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝑗 )  ↔  ( 𝐸 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝑗 )  =  ( 𝐸 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝑗 ) ) ) | 
						
							| 45 |  | oveq2 | ⊢ ( 𝑗  =  𝐸  →  ( 𝐸 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝑗 )  =  ( 𝐸 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝐸 ) ) | 
						
							| 46 |  | oveq2 | ⊢ ( 𝑗  =  𝐸  →  ( 𝐸 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝑗 )  =  ( 𝐸 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝐸 ) ) | 
						
							| 47 | 45 46 | eqeq12d | ⊢ ( 𝑗  =  𝐸  →  ( ( 𝐸 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝑗 )  =  ( 𝐸 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝑗 )  ↔  ( 𝐸 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝐸 )  =  ( 𝐸 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝐸 ) ) ) | 
						
							| 48 | 44 47 | 2ralsng | ⊢ ( ( 𝐸  ∈  𝑉  ∧  𝐸  ∈  𝑉 )  →  ( ∀ 𝑖  ∈  { 𝐸 } ∀ 𝑗  ∈  { 𝐸 } ( 𝑖 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝑗 )  =  ( 𝑖 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝑗 )  ↔  ( 𝐸 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝐸 )  =  ( 𝐸 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝐸 ) ) ) | 
						
							| 49 | 16 16 48 | syl2anc | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  →  ( ∀ 𝑖  ∈  { 𝐸 } ∀ 𝑗  ∈  { 𝐸 } ( 𝑖 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝑗 )  =  ( 𝑖 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝑗 )  ↔  ( 𝐸 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝐸 )  =  ( 𝐸 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝐸 ) ) ) | 
						
							| 50 | 49 | adantr | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( ∀ 𝑖  ∈  { 𝐸 } ∀ 𝑗  ∈  { 𝐸 } ( 𝑖 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝑗 )  =  ( 𝑖 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝑗 )  ↔  ( 𝐸 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝐸 )  =  ( 𝐸 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝐸 ) ) ) | 
						
							| 51 | 41 50 | mpbird | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ∀ 𝑖  ∈  { 𝐸 } ∀ 𝑗  ∈  { 𝐸 } ( 𝑖 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝑗 )  =  ( 𝑖 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝑗 ) ) | 
						
							| 52 | 1 2 3 4 5 | mat1rhmcl | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉  ∧  ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 )  ∈  𝐾 )  →  ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) )  ∈  𝐵 ) | 
						
							| 53 | 15 17 38 52 | syl3anc | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) )  ∈  𝐵 ) | 
						
							| 54 | 2 | matring | ⊢ ( ( { 𝐸 }  ∈  Fin  ∧  𝑅  ∈  Ring )  →  𝐴  ∈  Ring ) | 
						
							| 55 | 10 11 54 | sylancr | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  →  𝐴  ∈  Ring ) | 
						
							| 56 | 55 | adantr | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  𝐴  ∈  Ring ) | 
						
							| 57 | 3 7 | ringacl | ⊢ ( ( 𝐴  ∈  Ring  ∧  ( 𝐹 ‘ 𝑤 )  ∈  𝐵  ∧  ( 𝐹 ‘ 𝑦 )  ∈  𝐵 )  →  ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) )  ∈  𝐵 ) | 
						
							| 58 | 56 28 30 57 | syl3anc | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) )  ∈  𝐵 ) | 
						
							| 59 | 2 3 | eqmat | ⊢ ( ( ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) )  ∈  𝐵  ∧  ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) )  ∈  𝐵 )  →  ( ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) )  =  ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) )  ↔  ∀ 𝑖  ∈  { 𝐸 } ∀ 𝑗  ∈  { 𝐸 } ( 𝑖 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝑗 )  =  ( 𝑖 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝑗 ) ) ) | 
						
							| 60 | 53 58 59 | syl2anc | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) )  =  ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) )  ↔  ∀ 𝑖  ∈  { 𝐸 } ∀ 𝑗  ∈  { 𝐸 } ( 𝑖 ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) ) 𝑗 )  =  ( 𝑖 ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) 𝑗 ) ) ) | 
						
							| 61 | 51 60 | mpbird | ⊢ ( ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  ∧  ( 𝑤  ∈  𝐾  ∧  𝑦  ∈  𝐾 ) )  →  ( 𝐹 ‘ ( 𝑤 ( +g ‘ 𝑅 ) 𝑦 ) )  =  ( ( 𝐹 ‘ 𝑤 ) ( +g ‘ 𝐴 ) ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 62 | 1 3 6 7 9 13 14 61 | isghmd | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐸  ∈  𝑉 )  →  𝐹  ∈  ( 𝑅  GrpHom  𝐴 ) ) |