Definition df-mplcoe 15031

Description: Define the subalgebra of the power series algebra generated by the variables; this is the polynomial algebra (the set of power series with finite degree).

The index set (which has an element for each variable) is i, the coefficients are in ring r, and for each variable there is a "degree" such that the coefficient is zero for a term where the powers are all greater than those degrees. (Degree is in quotes because there is no guarantee that coefficients below that degree are nonzero, as we do not assume decidable equality for r). (Contributed by Mario Carneiro, 7-Jan-2015.) (Revised by AV, 25-Jun-2019.) (Revised by Jim Kingdon, 7-Oct-2025.)

Assertion

Ref	Expression
df-mplcoe	|- mPoly = ( i e. _V , r e. _V |-> [_ ( i mPwSer r ) / w ]_ ( w ↾s { f e. ( Base ` w ) | E. a e. ( NN0 ^m i ) A. b e. ( NN0 ^m i ) ( A. k e. i ( a ` k ) < ( b ` k ) -> ( f ` b ) = ( 0g ` r ) ) } ) )

Distinct variable group:   a, b, f, i, k, r, w

Detailed syntax breakdown of Definition df-mplcoe

Step	Hyp	Ref	Expression
1		cmpl 15029	. 2 class mPoly
2		vi	. . 3 setvar i
3		vr	. . 3 setvar r
4		cvv 2821	. . 3 class _V
5		vw	. . . 4 setvar w
6	2	cv 1401	. . . . 5 class i
7	3	cv 1401	. . . . 5 class r
8		cmps 15028	. . . . 5 class mPwSer
9	6, 7, 8	co 6079	. . . 4 class ( i mPwSer r )
10	5	cv 1401	. . . . 5 class w
11		vk	. . . . . . . . . . . . 13 setvar k
12	11	cv 1401	. . . . . . . . . . . 12 class k
13		va	. . . . . . . . . . . . 13 setvar a
14	13	cv 1401	. . . . . . . . . . . 12 class a
15	12, 14	cfv 5375	. . . . . . . . . . 11 class ( a ` k )
16		vb	. . . . . . . . . . . . 13 setvar b
17	16	cv 1401	. . . . . . . . . . . 12 class b
18	12, 17	cfv 5375	. . . . . . . . . . 11 class ( b ` k )
19		clt 8354	. . . . . . . . . . 11 class <
20	15, 18, 19	wbr 4128	. . . . . . . . . 10 wff ( a ` k ) < ( b ` k )
21	20, 11, 6	wral 2528	. . . . . . . . 9 wff A. k e. i ( a ` k ) < ( b ` k )
22		vf	. . . . . . . . . . . 12 setvar f
23	22	cv 1401	. . . . . . . . . . 11 class f
24	17, 23	cfv 5375	. . . . . . . . . 10 class ( f ` b )
25		c0g 13593	. . . . . . . . . . 11 class 0g
26	7, 25	cfv 5375	. . . . . . . . . 10 class ( 0g ` r )
27	24, 26	wceq 1402	. . . . . . . . 9 wff ( f ` b ) = ( 0g ` r )
28	21, 27	wi 4	. . . . . . . 8 wff ( A. k e. i ( a ` k ) < ( b ` k ) -> ( f ` b ) = ( 0g ` r ) )
29		cn0 9546	. . . . . . . . 9 class NN0
30		cmap 6916	. . . . . . . . 9 class ^m
31	29, 6, 30	co 6079	. . . . . . . 8 class ( NN0 ^m i )
32	28, 16, 31	wral 2528	. . . . . . 7 wff A. b e. ( NN0 ^m i ) ( A. k e. i ( a ` k ) < ( b ` k ) -> ( f ` b ) = ( 0g ` r ) )
33	32, 13, 31	wrex 2529	. . . . . 6 wff E. a e. ( NN0 ^m i ) A. b e. ( NN0 ^m i ) ( A. k e. i ( a ` k ) < ( b ` k ) -> ( f ` b ) = ( 0g ` r ) )
34		cbs 13335	. . . . . . 7 class Base
35	10, 34	cfv 5375	. . . . . 6 class ( Base ` w )
36	33, 22, 35	crab 2532	. . . . 5 class { f e. ( Base ` w ) | E. a e. ( NN0 ^m i ) A. b e. ( NN0 ^m i ) ( A. k e. i ( a ` k ) < ( b ` k ) -> ( f ` b ) = ( 0g ` r ) ) }
37		cress 13336	. . . . 5 class ↾s
38	10, 36, 37	co 6079	. . . 4 class ( w ↾s { f e. ( Base ` w ) | E. a e. ( NN0 ^m i ) A. b e. ( NN0 ^m i ) ( A. k e. i ( a ` k ) < ( b ` k ) -> ( f ` b ) = ( 0g ` r ) ) } )
39	5, 9, 38	csb 3147	. . 3 class [_ ( i mPwSer r ) / w ]_ ( w ↾s { f e. ( Base ` w ) | E. a e. ( NN0 ^m i ) A. b e. ( NN0 ^m i ) ( A. k e. i ( a ` k ) < ( b ` k ) -> ( f ` b ) = ( 0g ` r ) ) } )
40	2, 3, 4, 4, 39	cmpo 6081	. 2 class ( i e. _V , r e. _V |-> [_ ( i mPwSer r ) / w ]_ ( w ↾s { f e. ( Base ` w ) | E. a e. ( NN0 ^m i ) A. b e. ( NN0 ^m i ) ( A. k e. i ( a ` k ) < ( b ` k ) -> ( f ` b ) = ( 0g ` r ) ) } ) )
41	1, 40	wceq 1402	1 wff mPoly = ( i e. _V , r e. _V |-> [_ ( i mPwSer r ) / w ]_ ( w ↾s { f e. ( Base ` w ) | E. a e. ( NN0 ^m i ) A. b e. ( NN0 ^m i ) ( A. k e. i ( a ` k ) < ( b ` k ) -> ( f ` b ) = ( 0g ` r ) ) } ) )

This definition is referenced by:  reldmmpl  15063  mplvalcoe  15064  fnmpl  15067