| Step | Hyp | Ref | Expression | 
						
							| 1 |  | d1mat2pmat.t | ⊢ 𝑇  =  ( 𝑁  matToPolyMat  𝑅 ) | 
						
							| 2 |  | d1mat2pmat.b | ⊢ 𝐵  =  ( Base ‘ ( 𝑁  Mat  𝑅 ) ) | 
						
							| 3 |  | d1mat2pmat.p | ⊢ 𝑃  =  ( Poly1 ‘ 𝑅 ) | 
						
							| 4 |  | d1mat2pmat.s | ⊢ 𝑆  =  ( algSc ‘ 𝑃 ) | 
						
							| 5 |  | snfi | ⊢ { 𝐴 }  ∈  Fin | 
						
							| 6 |  | eleq1 | ⊢ ( 𝑁  =  { 𝐴 }  →  ( 𝑁  ∈  Fin  ↔  { 𝐴 }  ∈  Fin ) ) | 
						
							| 7 | 5 6 | mpbiri | ⊢ ( 𝑁  =  { 𝐴 }  →  𝑁  ∈  Fin ) | 
						
							| 8 | 7 | adantr | ⊢ ( ( 𝑁  =  { 𝐴 }  ∧  𝐴  ∈  𝑉 )  →  𝑁  ∈  Fin ) | 
						
							| 9 | 8 | 3ad2ant2 | ⊢ ( ( 𝑅  ∈  𝑉  ∧  ( 𝑁  =  { 𝐴 }  ∧  𝐴  ∈  𝑉 )  ∧  𝑀  ∈  𝐵 )  →  𝑁  ∈  Fin ) | 
						
							| 10 |  | simp1 | ⊢ ( ( 𝑅  ∈  𝑉  ∧  ( 𝑁  =  { 𝐴 }  ∧  𝐴  ∈  𝑉 )  ∧  𝑀  ∈  𝐵 )  →  𝑅  ∈  𝑉 ) | 
						
							| 11 |  | simp3 | ⊢ ( ( 𝑅  ∈  𝑉  ∧  ( 𝑁  =  { 𝐴 }  ∧  𝐴  ∈  𝑉 )  ∧  𝑀  ∈  𝐵 )  →  𝑀  ∈  𝐵 ) | 
						
							| 12 |  | eqid | ⊢ ( 𝑁  Mat  𝑅 )  =  ( 𝑁  Mat  𝑅 ) | 
						
							| 13 | 1 12 2 3 4 | mat2pmatval | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵 )  →  ( 𝑇 ‘ 𝑀 )  =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) ) ) | 
						
							| 14 | 9 10 11 13 | syl3anc | ⊢ ( ( 𝑅  ∈  𝑉  ∧  ( 𝑁  =  { 𝐴 }  ∧  𝐴  ∈  𝑉 )  ∧  𝑀  ∈  𝐵 )  →  ( 𝑇 ‘ 𝑀 )  =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) ) ) | 
						
							| 15 |  | id | ⊢ ( 𝐴  ∈  𝑉  →  𝐴  ∈  𝑉 ) | 
						
							| 16 |  | fvexd | ⊢ ( 𝐴  ∈  𝑉  →  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) )  ∈  V ) | 
						
							| 17 | 15 15 16 | 3jca | ⊢ ( 𝐴  ∈  𝑉  →  ( 𝐴  ∈  𝑉  ∧  𝐴  ∈  𝑉  ∧  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) )  ∈  V ) ) | 
						
							| 18 | 17 | adantl | ⊢ ( ( 𝑁  =  { 𝐴 }  ∧  𝐴  ∈  𝑉 )  →  ( 𝐴  ∈  𝑉  ∧  𝐴  ∈  𝑉  ∧  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) )  ∈  V ) ) | 
						
							| 19 | 18 | 3ad2ant2 | ⊢ ( ( 𝑅  ∈  𝑉  ∧  ( 𝑁  =  { 𝐴 }  ∧  𝐴  ∈  𝑉 )  ∧  𝑀  ∈  𝐵 )  →  ( 𝐴  ∈  𝑉  ∧  𝐴  ∈  𝑉  ∧  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) )  ∈  V ) ) | 
						
							| 20 |  | eqid | ⊢ ( 𝑖  ∈  { 𝐴 } ,  𝑗  ∈  { 𝐴 }  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  ( 𝑖  ∈  { 𝐴 } ,  𝑗  ∈  { 𝐴 }  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) ) | 
						
							| 21 |  | fvoveq1 | ⊢ ( 𝑖  =  𝐴  →  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) )  =  ( 𝑆 ‘ ( 𝐴 𝑀 𝑗 ) ) ) | 
						
							| 22 |  | oveq2 | ⊢ ( 𝑗  =  𝐴  →  ( 𝐴 𝑀 𝑗 )  =  ( 𝐴 𝑀 𝐴 ) ) | 
						
							| 23 | 22 | fveq2d | ⊢ ( 𝑗  =  𝐴  →  ( 𝑆 ‘ ( 𝐴 𝑀 𝑗 ) )  =  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) ) | 
						
							| 24 | 20 21 23 | mposn | ⊢ ( ( 𝐴  ∈  𝑉  ∧  𝐴  ∈  𝑉  ∧  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) )  ∈  V )  →  ( 𝑖  ∈  { 𝐴 } ,  𝑗  ∈  { 𝐴 }  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  { 〈 〈 𝐴 ,  𝐴 〉 ,  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) 〉 } ) | 
						
							| 25 | 19 24 | syl | ⊢ ( ( 𝑅  ∈  𝑉  ∧  ( 𝑁  =  { 𝐴 }  ∧  𝐴  ∈  𝑉 )  ∧  𝑀  ∈  𝐵 )  →  ( 𝑖  ∈  { 𝐴 } ,  𝑗  ∈  { 𝐴 }  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  { 〈 〈 𝐴 ,  𝐴 〉 ,  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) 〉 } ) | 
						
							| 26 |  | mpoeq12 | ⊢ ( ( 𝑁  =  { 𝐴 }  ∧  𝑁  =  { 𝐴 } )  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  ( 𝑖  ∈  { 𝐴 } ,  𝑗  ∈  { 𝐴 }  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) ) ) | 
						
							| 27 | 26 | eqeq1d | ⊢ ( ( 𝑁  =  { 𝐴 }  ∧  𝑁  =  { 𝐴 } )  →  ( ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  { 〈 〈 𝐴 ,  𝐴 〉 ,  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) 〉 }  ↔  ( 𝑖  ∈  { 𝐴 } ,  𝑗  ∈  { 𝐴 }  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  { 〈 〈 𝐴 ,  𝐴 〉 ,  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) 〉 } ) ) | 
						
							| 28 | 27 | anidms | ⊢ ( 𝑁  =  { 𝐴 }  →  ( ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  { 〈 〈 𝐴 ,  𝐴 〉 ,  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) 〉 }  ↔  ( 𝑖  ∈  { 𝐴 } ,  𝑗  ∈  { 𝐴 }  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  { 〈 〈 𝐴 ,  𝐴 〉 ,  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) 〉 } ) ) | 
						
							| 29 | 28 | adantr | ⊢ ( ( 𝑁  =  { 𝐴 }  ∧  𝐴  ∈  𝑉 )  →  ( ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  { 〈 〈 𝐴 ,  𝐴 〉 ,  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) 〉 }  ↔  ( 𝑖  ∈  { 𝐴 } ,  𝑗  ∈  { 𝐴 }  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  { 〈 〈 𝐴 ,  𝐴 〉 ,  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) 〉 } ) ) | 
						
							| 30 | 29 | 3ad2ant2 | ⊢ ( ( 𝑅  ∈  𝑉  ∧  ( 𝑁  =  { 𝐴 }  ∧  𝐴  ∈  𝑉 )  ∧  𝑀  ∈  𝐵 )  →  ( ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  { 〈 〈 𝐴 ,  𝐴 〉 ,  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) 〉 }  ↔  ( 𝑖  ∈  { 𝐴 } ,  𝑗  ∈  { 𝐴 }  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  { 〈 〈 𝐴 ,  𝐴 〉 ,  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) 〉 } ) ) | 
						
							| 31 | 25 30 | mpbird | ⊢ ( ( 𝑅  ∈  𝑉  ∧  ( 𝑁  =  { 𝐴 }  ∧  𝐴  ∈  𝑉 )  ∧  𝑀  ∈  𝐵 )  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( 𝑆 ‘ ( 𝑖 𝑀 𝑗 ) ) )  =  { 〈 〈 𝐴 ,  𝐴 〉 ,  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) 〉 } ) | 
						
							| 32 | 14 31 | eqtrd | ⊢ ( ( 𝑅  ∈  𝑉  ∧  ( 𝑁  =  { 𝐴 }  ∧  𝐴  ∈  𝑉 )  ∧  𝑀  ∈  𝐵 )  →  ( 𝑇 ‘ 𝑀 )  =  { 〈 〈 𝐴 ,  𝐴 〉 ,  ( 𝑆 ‘ ( 𝐴 𝑀 𝐴 ) ) 〉 } ) |