| Step | Hyp | Ref | Expression | 
						
							| 1 |  | decpmate.p | ⊢ 𝑃  =  ( Poly1 ‘ 𝑅 ) | 
						
							| 2 |  | decpmate.c | ⊢ 𝐶  =  ( 𝑁  Mat  𝑃 ) | 
						
							| 3 |  | decpmate.b | ⊢ 𝐵  =  ( Base ‘ 𝐶 ) | 
						
							| 4 |  | decpmatcl.a | ⊢ 𝐴  =  ( 𝑁  Mat  𝑅 ) | 
						
							| 5 |  | decpmatcl.d | ⊢ 𝐷  =  ( Base ‘ 𝐴 ) | 
						
							| 6 | 2 3 | decpmatval | ⊢ ( ( 𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  →  ( 𝑀  decompPMat  𝐾 )  =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 𝑀 𝑗 ) ) ‘ 𝐾 ) ) ) | 
						
							| 7 | 6 | 3adant1 | ⊢ ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  →  ( 𝑀  decompPMat  𝐾 )  =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 𝑀 𝑗 ) ) ‘ 𝐾 ) ) ) | 
						
							| 8 |  | eqid | ⊢ ( Base ‘ 𝑅 )  =  ( Base ‘ 𝑅 ) | 
						
							| 9 | 2 3 | matrcl | ⊢ ( 𝑀  ∈  𝐵  →  ( 𝑁  ∈  Fin  ∧  𝑃  ∈  V ) ) | 
						
							| 10 | 9 | simpld | ⊢ ( 𝑀  ∈  𝐵  →  𝑁  ∈  Fin ) | 
						
							| 11 | 10 | 3ad2ant2 | ⊢ ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  →  𝑁  ∈  Fin ) | 
						
							| 12 |  | simp1 | ⊢ ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  →  𝑅  ∈  𝑉 ) | 
						
							| 13 |  | eqid | ⊢ ( Base ‘ 𝑃 )  =  ( Base ‘ 𝑃 ) | 
						
							| 14 |  | simp2 | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  ∧  𝑖  ∈  𝑁  ∧  𝑗  ∈  𝑁 )  →  𝑖  ∈  𝑁 ) | 
						
							| 15 |  | simp3 | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  ∧  𝑖  ∈  𝑁  ∧  𝑗  ∈  𝑁 )  →  𝑗  ∈  𝑁 ) | 
						
							| 16 |  | simp2 | ⊢ ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  →  𝑀  ∈  𝐵 ) | 
						
							| 17 | 16 | 3ad2ant1 | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  ∧  𝑖  ∈  𝑁  ∧  𝑗  ∈  𝑁 )  →  𝑀  ∈  𝐵 ) | 
						
							| 18 | 2 13 3 14 15 17 | matecld | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  ∧  𝑖  ∈  𝑁  ∧  𝑗  ∈  𝑁 )  →  ( 𝑖 𝑀 𝑗 )  ∈  ( Base ‘ 𝑃 ) ) | 
						
							| 19 |  | simp3 | ⊢ ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  →  𝐾  ∈  ℕ0 ) | 
						
							| 20 | 19 | 3ad2ant1 | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  ∧  𝑖  ∈  𝑁  ∧  𝑗  ∈  𝑁 )  →  𝐾  ∈  ℕ0 ) | 
						
							| 21 |  | eqid | ⊢ ( coe1 ‘ ( 𝑖 𝑀 𝑗 ) )  =  ( coe1 ‘ ( 𝑖 𝑀 𝑗 ) ) | 
						
							| 22 | 21 13 1 8 | coe1fvalcl | ⊢ ( ( ( 𝑖 𝑀 𝑗 )  ∈  ( Base ‘ 𝑃 )  ∧  𝐾  ∈  ℕ0 )  →  ( ( coe1 ‘ ( 𝑖 𝑀 𝑗 ) ) ‘ 𝐾 )  ∈  ( Base ‘ 𝑅 ) ) | 
						
							| 23 | 18 20 22 | syl2anc | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  ∧  𝑖  ∈  𝑁  ∧  𝑗  ∈  𝑁 )  →  ( ( coe1 ‘ ( 𝑖 𝑀 𝑗 ) ) ‘ 𝐾 )  ∈  ( Base ‘ 𝑅 ) ) | 
						
							| 24 | 4 8 5 11 12 23 | matbas2d | ⊢ ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 𝑀 𝑗 ) ) ‘ 𝐾 ) )  ∈  𝐷 ) | 
						
							| 25 | 7 24 | eqeltrd | ⊢ ( ( 𝑅  ∈  𝑉  ∧  𝑀  ∈  𝐵  ∧  𝐾  ∈  ℕ0 )  →  ( 𝑀  decompPMat  𝐾 )  ∈  𝐷 ) |