Metamath Proof Explorer


Theorem mplmul

Description: The multiplication operation on multivariate polynomials. (Contributed by Mario Carneiro, 9-Jan-2015)

Ref Expression
Hypotheses mplmul.p
|- P = ( I mPoly R )
mplmul.b
|- B = ( Base ` P )
mplmul.m
|- .x. = ( .r ` R )
mplmul.t
|- .xb = ( .r ` P )
mplmul.d
|- D = { h e. ( NN0 ^m I ) | ( `' h " NN ) e. Fin }
mplmul.f
|- ( ph -> F e. B )
mplmul.g
|- ( ph -> G e. B )
Assertion mplmul
|- ( ph -> ( F .xb G ) = ( k e. D |-> ( R gsum ( x e. { y e. D | y oR <_ k } |-> ( ( F ` x ) .x. ( G ` ( k oF - x ) ) ) ) ) ) )

Proof

Step Hyp Ref Expression
1 mplmul.p
 |-  P = ( I mPoly R )
2 mplmul.b
 |-  B = ( Base ` P )
3 mplmul.m
 |-  .x. = ( .r ` R )
4 mplmul.t
 |-  .xb = ( .r ` P )
5 mplmul.d
 |-  D = { h e. ( NN0 ^m I ) | ( `' h " NN ) e. Fin }
6 mplmul.f
 |-  ( ph -> F e. B )
7 mplmul.g
 |-  ( ph -> G e. B )
8 eqid
 |-  ( I mPwSer R ) = ( I mPwSer R )
9 eqid
 |-  ( Base ` ( I mPwSer R ) ) = ( Base ` ( I mPwSer R ) )
10 1 8 4 mplmulr
 |-  .xb = ( .r ` ( I mPwSer R ) )
11 1 8 2 9 mplbasss
 |-  B C_ ( Base ` ( I mPwSer R ) )
12 11 6 sselid
 |-  ( ph -> F e. ( Base ` ( I mPwSer R ) ) )
13 11 7 sselid
 |-  ( ph -> G e. ( Base ` ( I mPwSer R ) ) )
14 8 9 3 10 5 12 13 psrmulfval
 |-  ( ph -> ( F .xb G ) = ( k e. D |-> ( R gsum ( x e. { y e. D | y oR <_ k } |-> ( ( F ` x ) .x. ( G ` ( k oF - x ) ) ) ) ) ) )