| Step | Hyp | Ref | Expression | 
						
							| 1 |  | smatcl.a |  |-  A = ( ( 1 ... N ) Mat R ) | 
						
							| 2 |  | smatcl.b |  |-  B = ( Base ` A ) | 
						
							| 3 |  | smatcl.c |  |-  C = ( Base ` ( ( 1 ... ( N - 1 ) ) Mat R ) ) | 
						
							| 4 |  | smatcl.s |  |-  S = ( K ( subMat1 ` M ) L ) | 
						
							| 5 |  | smatcl.n |  |-  ( ph -> N e. NN ) | 
						
							| 6 |  | smatcl.k |  |-  ( ph -> K e. ( 1 ... N ) ) | 
						
							| 7 |  | smatcl.l |  |-  ( ph -> L e. ( 1 ... N ) ) | 
						
							| 8 |  | smatcl.m |  |-  ( ph -> M e. B ) | 
						
							| 9 |  | eqid |  |-  ( Base ` R ) = ( Base ` R ) | 
						
							| 10 | 1 9 2 | matbas2i |  |-  ( M e. B -> M e. ( ( Base ` R ) ^m ( ( 1 ... N ) X. ( 1 ... N ) ) ) ) | 
						
							| 11 | 8 10 | syl |  |-  ( ph -> M e. ( ( Base ` R ) ^m ( ( 1 ... N ) X. ( 1 ... N ) ) ) ) | 
						
							| 12 | 4 5 5 6 7 11 | smatrcl |  |-  ( ph -> S e. ( ( Base ` R ) ^m ( ( 1 ... ( N - 1 ) ) X. ( 1 ... ( N - 1 ) ) ) ) ) | 
						
							| 13 |  | fzfi |  |-  ( 1 ... ( N - 1 ) ) e. Fin | 
						
							| 14 | 1 2 | matrcl |  |-  ( M e. B -> ( ( 1 ... N ) e. Fin /\ R e. _V ) ) | 
						
							| 15 | 14 | simprd |  |-  ( M e. B -> R e. _V ) | 
						
							| 16 | 8 15 | syl |  |-  ( ph -> R e. _V ) | 
						
							| 17 |  | eqid |  |-  ( ( 1 ... ( N - 1 ) ) Mat R ) = ( ( 1 ... ( N - 1 ) ) Mat R ) | 
						
							| 18 | 17 9 | matbas2 |  |-  ( ( ( 1 ... ( N - 1 ) ) e. Fin /\ R e. _V ) -> ( ( Base ` R ) ^m ( ( 1 ... ( N - 1 ) ) X. ( 1 ... ( N - 1 ) ) ) ) = ( Base ` ( ( 1 ... ( N - 1 ) ) Mat R ) ) ) | 
						
							| 19 | 13 16 18 | sylancr |  |-  ( ph -> ( ( Base ` R ) ^m ( ( 1 ... ( N - 1 ) ) X. ( 1 ... ( N - 1 ) ) ) ) = ( Base ` ( ( 1 ... ( N - 1 ) ) Mat R ) ) ) | 
						
							| 20 | 19 | eleq2d |  |-  ( ph -> ( S e. ( ( Base ` R ) ^m ( ( 1 ... ( N - 1 ) ) X. ( 1 ... ( N - 1 ) ) ) ) <-> S e. ( Base ` ( ( 1 ... ( N - 1 ) ) Mat R ) ) ) ) | 
						
							| 21 | 12 20 | mpbid |  |-  ( ph -> S e. ( Base ` ( ( 1 ... ( N - 1 ) ) Mat R ) ) ) | 
						
							| 22 | 21 3 | eleqtrrdi |  |-  ( ph -> S e. C ) |