| Step | Hyp | Ref | Expression | 
						
							| 1 |  | decpmatmul.p | ⊢ 𝑃  =  ( Poly1 ‘ 𝑅 ) | 
						
							| 2 |  | decpmatmul.c | ⊢ 𝐶  =  ( 𝑁  Mat  𝑃 ) | 
						
							| 3 |  | decpmatmul.b | ⊢ 𝐵  =  ( Base ‘ 𝐶 ) | 
						
							| 4 |  | decpmatmul.a | ⊢ 𝐴  =  ( 𝑁  Mat  𝑅 ) | 
						
							| 5 |  | decpmatmulsumfsupp.m | ⊢  ·   =  ( .r ‘ 𝐴 ) | 
						
							| 6 |  | decpmatmulsumfsupp.0 | ⊢  0   =  ( 0g ‘ 𝐴 ) | 
						
							| 7 | 6 | fvexi | ⊢  0   ∈  V | 
						
							| 8 | 7 | a1i | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →   0   ∈  V ) | 
						
							| 9 |  | ovexd | ⊢ ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑙  ∈  ℕ0 )  →  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑙 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑙  −  𝑘 ) ) ) ) )  ∈  V ) | 
						
							| 10 |  | oveq2 | ⊢ ( 𝑙  =  𝑛  →  ( 0 ... 𝑙 )  =  ( 0 ... 𝑛 ) ) | 
						
							| 11 |  | oveq1 | ⊢ ( 𝑙  =  𝑛  →  ( 𝑙  −  𝑘 )  =  ( 𝑛  −  𝑘 ) ) | 
						
							| 12 | 11 | oveq2d | ⊢ ( 𝑙  =  𝑛  →  ( 𝑦  decompPMat  ( 𝑙  −  𝑘 ) )  =  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) | 
						
							| 13 | 12 | oveq2d | ⊢ ( 𝑙  =  𝑛  →  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑙  −  𝑘 ) ) )  =  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) | 
						
							| 14 | 10 13 | mpteq12dv | ⊢ ( 𝑙  =  𝑛  →  ( 𝑘  ∈  ( 0 ... 𝑙 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑙  −  𝑘 ) ) ) )  =  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) ) | 
						
							| 15 | 14 | oveq2d | ⊢ ( 𝑙  =  𝑛  →  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑙 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑙  −  𝑘 ) ) ) ) )  =  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) ) ) | 
						
							| 16 |  | simpll | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  𝑁  ∈  Fin ) | 
						
							| 17 |  | simplr | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  𝑅  ∈  Ring ) | 
						
							| 18 | 1 2 | pmatring | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  →  𝐶  ∈  Ring ) | 
						
							| 19 | 18 | anim1i | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( 𝐶  ∈  Ring  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) ) ) | 
						
							| 20 |  | 3anass | ⊢ ( ( 𝐶  ∈  Ring  ∧  𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 )  ↔  ( 𝐶  ∈  Ring  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) ) ) | 
						
							| 21 | 19 20 | sylibr | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( 𝐶  ∈  Ring  ∧  𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) ) | 
						
							| 22 |  | eqid | ⊢ ( .r ‘ 𝐶 )  =  ( .r ‘ 𝐶 ) | 
						
							| 23 | 3 22 | ringcl | ⊢ ( ( 𝐶  ∈  Ring  ∧  𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 )  →  ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 )  ∈  𝐵 ) | 
						
							| 24 | 21 23 | syl | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 )  ∈  𝐵 ) | 
						
							| 25 |  | eqid | ⊢ ( 0g ‘ 𝑅 )  =  ( 0g ‘ 𝑅 ) | 
						
							| 26 | 1 2 3 25 | pmatcoe1fsupp | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring  ∧  ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 )  ∈  𝐵 )  →  ∃ 𝑠  ∈  ℕ0 ∀ 𝑛  ∈  ℕ0 ( 𝑠  <  𝑛  →  ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) ) ) | 
						
							| 27 | 16 17 24 26 | syl3anc | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ∃ 𝑠  ∈  ℕ0 ∀ 𝑛  ∈  ℕ0 ( 𝑠  <  𝑛  →  ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) ) ) | 
						
							| 28 |  | fvoveq1 | ⊢ ( 𝑎  =  𝑖  →  ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) )  =  ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ) | 
						
							| 29 | 28 | fveq1d | ⊢ ( 𝑎  =  𝑖  →  ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 ) ) | 
						
							| 30 | 29 | eqeq1d | ⊢ ( 𝑎  =  𝑖  →  ( ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 )  ↔  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) ) ) | 
						
							| 31 |  | oveq2 | ⊢ ( 𝑏  =  𝑗  →  ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 )  =  ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) | 
						
							| 32 | 31 | fveq2d | ⊢ ( 𝑏  =  𝑗  →  ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) )  =  ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ) | 
						
							| 33 | 32 | fveq1d | ⊢ ( 𝑏  =  𝑗  →  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) ) | 
						
							| 34 | 33 | eqeq1d | ⊢ ( 𝑏  =  𝑗  →  ( ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 )  ↔  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) ) ) | 
						
							| 35 | 30 34 | rspc2va | ⊢ ( ( ( 𝑖  ∈  𝑁  ∧  𝑗  ∈  𝑁 )  ∧  ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) )  →  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) ) | 
						
							| 36 | 35 | expcom | ⊢ ( ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 )  →  ( ( 𝑖  ∈  𝑁  ∧  𝑗  ∈  𝑁 )  →  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) ) ) | 
						
							| 37 | 36 | adantl | ⊢ ( ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  ∧  ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) )  →  ( ( 𝑖  ∈  𝑁  ∧  𝑗  ∈  𝑁 )  →  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) ) ) | 
						
							| 38 | 37 | 3impib | ⊢ ( ( ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  ∧  ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) )  ∧  𝑖  ∈  𝑁  ∧  𝑗  ∈  𝑁 )  →  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) ) | 
						
							| 39 | 38 | mpoeq3dva | ⊢ ( ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  ∧  ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) )  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) )  =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( 0g ‘ 𝑅 ) ) ) | 
						
							| 40 | 4 25 | mat0op | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  →  ( 0g ‘ 𝐴 )  =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( 0g ‘ 𝑅 ) ) ) | 
						
							| 41 | 6 40 | eqtrid | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  →   0   =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( 0g ‘ 𝑅 ) ) ) | 
						
							| 42 | 41 | ad3antrrr | ⊢ ( ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  ∧  ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) )  →   0   =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( 0g ‘ 𝑅 ) ) ) | 
						
							| 43 | 39 42 | eqtr4d | ⊢ ( ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  ∧  ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) )  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) )  =   0  ) | 
						
							| 44 | 43 | ex | ⊢ ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  →  ( ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 )  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) )  =   0  ) ) | 
						
							| 45 | 44 | imim2d | ⊢ ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  →  ( ( 𝑠  <  𝑛  →  ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) )  →  ( 𝑠  <  𝑛  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) )  =   0  ) ) ) | 
						
							| 46 | 45 | ralimdva | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( ∀ 𝑛  ∈  ℕ0 ( 𝑠  <  𝑛  →  ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) )  →  ∀ 𝑛  ∈  ℕ0 ( 𝑠  <  𝑛  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) )  =   0  ) ) ) | 
						
							| 47 | 46 | reximdv | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( ∃ 𝑠  ∈  ℕ0 ∀ 𝑛  ∈  ℕ0 ( 𝑠  <  𝑛  →  ∀ 𝑎  ∈  𝑁 ∀ 𝑏  ∈  𝑁 ( ( coe1 ‘ ( 𝑎 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑏 ) ) ‘ 𝑛 )  =  ( 0g ‘ 𝑅 ) )  →  ∃ 𝑠  ∈  ℕ0 ∀ 𝑛  ∈  ℕ0 ( 𝑠  <  𝑛  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) )  =   0  ) ) ) | 
						
							| 48 | 27 47 | mpd | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ∃ 𝑠  ∈  ℕ0 ∀ 𝑛  ∈  ℕ0 ( 𝑠  <  𝑛  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) )  =   0  ) ) | 
						
							| 49 | 5 | oveqi | ⊢ ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) )  =  ( ( 𝑥  decompPMat  𝑘 ) ( .r ‘ 𝐴 ) ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) | 
						
							| 50 | 49 | a1i | ⊢ ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  →  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) )  =  ( ( 𝑥  decompPMat  𝑘 ) ( .r ‘ 𝐴 ) ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) | 
						
							| 51 | 50 | mpteq2dv | ⊢ ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  →  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) )  =  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 ) ( .r ‘ 𝐴 ) ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) ) | 
						
							| 52 | 51 | oveq2d | ⊢ ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  →  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) )  =  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 ) ( .r ‘ 𝐴 ) ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) ) ) | 
						
							| 53 | 1 2 3 4 | decpmatmul | ⊢ ( ( 𝑅  ∈  Ring  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 )  ∧  𝑛  ∈  ℕ0 )  →  ( ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 )  decompPMat  𝑛 )  =  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 ) ( .r ‘ 𝐴 ) ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) ) ) | 
						
							| 54 | 53 | ad4ant234 | ⊢ ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  →  ( ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 )  decompPMat  𝑛 )  =  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 ) ( .r ‘ 𝐴 ) ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) ) ) | 
						
							| 55 | 2 3 | decpmatval | ⊢ ( ( ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 )  ∈  𝐵  ∧  𝑛  ∈  ℕ0 )  →  ( ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 )  decompPMat  𝑛 )  =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) ) ) | 
						
							| 56 | 24 55 | sylan | ⊢ ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  →  ( ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 )  decompPMat  𝑛 )  =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) ) ) | 
						
							| 57 | 52 54 56 | 3eqtr2d | ⊢ ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  →  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) )  =  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) ) ) | 
						
							| 58 | 57 | eqeq1d | ⊢ ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  →  ( ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) )  =   0   ↔  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) )  =   0  ) ) | 
						
							| 59 | 58 | imbi2d | ⊢ ( ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  ∧  𝑛  ∈  ℕ0 )  →  ( ( 𝑠  <  𝑛  →  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) )  =   0  )  ↔  ( 𝑠  <  𝑛  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) )  =   0  ) ) ) | 
						
							| 60 | 59 | ralbidva | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( ∀ 𝑛  ∈  ℕ0 ( 𝑠  <  𝑛  →  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) )  =   0  )  ↔  ∀ 𝑛  ∈  ℕ0 ( 𝑠  <  𝑛  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) )  =   0  ) ) ) | 
						
							| 61 | 60 | rexbidv | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( ∃ 𝑠  ∈  ℕ0 ∀ 𝑛  ∈  ℕ0 ( 𝑠  <  𝑛  →  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) )  =   0  )  ↔  ∃ 𝑠  ∈  ℕ0 ∀ 𝑛  ∈  ℕ0 ( 𝑠  <  𝑛  →  ( 𝑖  ∈  𝑁 ,  𝑗  ∈  𝑁  ↦  ( ( coe1 ‘ ( 𝑖 ( 𝑥 ( .r ‘ 𝐶 ) 𝑦 ) 𝑗 ) ) ‘ 𝑛 ) )  =   0  ) ) ) | 
						
							| 62 | 48 61 | mpbird | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ∃ 𝑠  ∈  ℕ0 ∀ 𝑛  ∈  ℕ0 ( 𝑠  <  𝑛  →  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑛 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑛  −  𝑘 ) ) ) ) )  =   0  ) ) | 
						
							| 63 | 8 9 15 62 | mptnn0fsuppd | ⊢ ( ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( 𝑙  ∈  ℕ0  ↦  ( 𝐴  Σg  ( 𝑘  ∈  ( 0 ... 𝑙 )  ↦  ( ( 𝑥  decompPMat  𝑘 )  ·  ( 𝑦  decompPMat  ( 𝑙  −  𝑘 ) ) ) ) ) )  finSupp   0  ) |