Metamath Proof Explorer


Theorem smatcl

Description: Closure of the square submatrix: if M is a square matrix of dimension N with indices in ( 1 ... N ) , then a submatrix of M is of dimension ( N - 1 ) . (Contributed by Thierry Arnoux, 19-Aug-2020)

Ref Expression
Hypotheses smatcl.a
|- A = ( ( 1 ... N ) Mat R )
smatcl.b
|- B = ( Base ` A )
smatcl.c
|- C = ( Base ` ( ( 1 ... ( N - 1 ) ) Mat R ) )
smatcl.s
|- S = ( K ( subMat1 ` M ) L )
smatcl.n
|- ( ph -> N e. NN )
smatcl.k
|- ( ph -> K e. ( 1 ... N ) )
smatcl.l
|- ( ph -> L e. ( 1 ... N ) )
smatcl.m
|- ( ph -> M e. B )
Assertion smatcl
|- ( ph -> S e. C )

Proof

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 )