Metamath Proof Explorer


Theorem mplvrpmmhm

Description: The action of permuting variables in a multivariate polynomial is a monoid homomorphism. (Contributed by Thierry Arnoux, 11-Jan-2026)

Ref Expression
Hypotheses mplvrpmga.1 S = SymGrp I
mplvrpmga.2 P = Base S
mplvrpmga.3 M = Base I mPoly R
mplvrpmga.4 A = d P , f M x h 0 I | finSupp 0 h f x d
mplvrpmga.5 φ I V
mplvrpmmhm.f F = f M D A f
mplvrpmmhm.w W = I mPoly R
mplvrpmmhm.1 φ R Ring
mplvrpmmhm.2 φ D P
Assertion mplvrpmmhm φ F W MndHom W

Proof

Step Hyp Ref Expression
1 mplvrpmga.1 S = SymGrp I
2 mplvrpmga.2 P = Base S
3 mplvrpmga.3 M = Base I mPoly R
4 mplvrpmga.4 A = d P , f M x h 0 I | finSupp 0 h f x d
5 mplvrpmga.5 φ I V
6 mplvrpmmhm.f F = f M D A f
7 mplvrpmmhm.w W = I mPoly R
8 mplvrpmmhm.1 φ R Ring
9 mplvrpmmhm.2 φ D P
10 7 fveq2i Base W = Base I mPoly R
11 3 10 eqtr4i M = Base W
12 eqid + W = + W
13 eqid 0 W = 0 W
14 7 5 8 mplringd φ W Ring
15 14 ringgrpd φ W Grp
16 15 grpmndd φ W Mnd
17 1 2 3 4 5 mplvrpmga φ A S GrpAct M
18 2 gaf A S GrpAct M A : P × M M
19 17 18 syl φ A : P × M M
20 19 fovcld φ D P f M D A f M
21 20 3expa φ D P f M D A f M
22 21 an32s φ f M D P D A f M
23 9 22 mpidan φ f M D A f M
24 23 6 fmptd φ F : M M
25 eqid Base R = Base R
26 eqid h 0 I | finSupp 0 h = h 0 I | finSupp 0 h
27 26 psrbasfsupp h 0 I | finSupp 0 h = h 0 I | h -1 Fin
28 simplr φ i M j M i M
29 7 25 11 27 28 mplelf φ i M j M i : h 0 I | finSupp 0 h Base R
30 29 adantr φ i M j M x h 0 I | finSupp 0 h i : h 0 I | finSupp 0 h Base R
31 30 ffnd φ i M j M x h 0 I | finSupp 0 h i Fn h 0 I | finSupp 0 h
32 simpr φ i M j M j M
33 7 25 11 27 32 mplelf φ i M j M j : h 0 I | finSupp 0 h Base R
34 33 adantr φ i M j M x h 0 I | finSupp 0 h j : h 0 I | finSupp 0 h Base R
35 34 ffnd φ i M j M x h 0 I | finSupp 0 h j Fn h 0 I | finSupp 0 h
36 ovex 0 I V
37 36 rabex h 0 I | finSupp 0 h V
38 37 a1i φ i M j M x h 0 I | finSupp 0 h h 0 I | finSupp 0 h V
39 breq1 h = x D finSupp 0 h finSupp 0 x D
40 nn0ex 0 V
41 40 a1i φ i M j M x h 0 I | finSupp 0 h 0 V
42 5 ad3antrrr φ i M j M x h 0 I | finSupp 0 h I V
43 breq1 h = x finSupp 0 h finSupp 0 x
44 43 elrab x h 0 I | finSupp 0 h x 0 I finSupp 0 x
45 44 bilani φ x h 0 I | finSupp 0 h x 0 I finSupp 0 x
46 45 simpld φ x h 0 I | finSupp 0 h x 0 I
47 46 elmaprd φ x h 0 I | finSupp 0 h x : I 0
48 47 ad4ant14 φ i M j M x h 0 I | finSupp 0 h x : I 0
49 1 2 symgbasf1o D P D : I 1-1 onto I
50 9 49 syl φ D : I 1-1 onto I
51 f1of D : I 1-1 onto I D : I I
52 50 51 syl φ D : I I
53 52 ad3antrrr φ i M j M x h 0 I | finSupp 0 h D : I I
54 48 53 fcod φ i M j M x h 0 I | finSupp 0 h x D : I 0
55 41 42 54 elmapdd φ i M j M x h 0 I | finSupp 0 h x D 0 I
56 45 simprd φ x h 0 I | finSupp 0 h finSupp 0 x
57 50 adantr φ x h 0 I | finSupp 0 h D : I 1-1 onto I
58 f1of1 D : I 1-1 onto I D : I 1-1 I
59 57 58 syl φ x h 0 I | finSupp 0 h D : I 1-1 I
60 0nn0 0 0
61 60 a1i φ x h 0 I | finSupp 0 h 0 0
62 simpr φ x h 0 I | finSupp 0 h x h 0 I | finSupp 0 h
63 56 59 61 62 fsuppco φ x h 0 I | finSupp 0 h finSupp 0 x D
64 63 ad4ant14 φ i M j M x h 0 I | finSupp 0 h finSupp 0 x D
65 39 55 64 elrabd φ i M j M x h 0 I | finSupp 0 h x D h 0 I | finSupp 0 h
66 fnfvof i Fn h 0 I | finSupp 0 h j Fn h 0 I | finSupp 0 h h 0 I | finSupp 0 h V x D h 0 I | finSupp 0 h i + R f j x D = i x D + R j x D
67 31 35 38 65 66 syl22anc φ i M j M x h 0 I | finSupp 0 h i + R f j x D = i x D + R j x D
68 oveq2 f = i D A f = D A i
69 4 a1i φ i M j M A = d P , f M x h 0 I | finSupp 0 h f x d
70 simpr d = D f = i f = i
71 coeq2 d = D x d = x D
72 71 adantr d = D f = i x d = x D
73 70 72 fveq12d d = D f = i f x d = i x D
74 73 mpteq2dv d = D f = i x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h i x D
75 74 adantl φ i M j M d = D f = i x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h i x D
76 9 ad2antrr φ i M j M D P
77 37 a1i φ i M j M h 0 I | finSupp 0 h V
78 77 mptexd φ i M j M x h 0 I | finSupp 0 h i x D V
79 69 75 76 28 78 ovmpod φ i M j M D A i = x h 0 I | finSupp 0 h i x D
80 68 79 sylan9eqr φ i M j M f = i D A f = x h 0 I | finSupp 0 h i x D
81 6 80 28 78 fvmptd2 φ i M j M F i = x h 0 I | finSupp 0 h i x D
82 fvexd φ i M j M x h 0 I | finSupp 0 h i x D V
83 81 82 fvmpt2d φ i M j M x h 0 I | finSupp 0 h F i x = i x D
84 oveq2 f = j D A f = D A j
85 simpr d = D f = j f = j
86 71 adantr d = D f = j x d = x D
87 85 86 fveq12d d = D f = j f x d = j x D
88 87 mpteq2dv d = D f = j x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h j x D
89 88 adantl φ i M j M d = D f = j x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h j x D
90 77 mptexd φ i M j M x h 0 I | finSupp 0 h j x D V
91 69 89 76 32 90 ovmpod φ i M j M D A j = x h 0 I | finSupp 0 h j x D
92 84 91 sylan9eqr φ i M j M f = j D A f = x h 0 I | finSupp 0 h j x D
93 6 92 32 90 fvmptd2 φ i M j M F j = x h 0 I | finSupp 0 h j x D
94 fvexd φ i M j M x h 0 I | finSupp 0 h j x D V
95 93 94 fvmpt2d φ i M j M x h 0 I | finSupp 0 h F j x = j x D
96 83 95 oveq12d φ i M j M x h 0 I | finSupp 0 h F i x + R F j x = i x D + R j x D
97 67 96 eqtr4d φ i M j M x h 0 I | finSupp 0 h i + R f j x D = F i x + R F j x
98 97 mpteq2dva φ i M j M x h 0 I | finSupp 0 h i + R f j x D = x h 0 I | finSupp 0 h F i x + R F j x
99 24 ad2antrr φ i M j M F : M M
100 99 28 ffvelcdmd φ i M j M F i M
101 7 25 11 27 100 mplelf φ i M j M F i : h 0 I | finSupp 0 h Base R
102 101 ffnd φ i M j M F i Fn h 0 I | finSupp 0 h
103 99 32 ffvelcdmd φ i M j M F j M
104 7 25 11 27 103 mplelf φ i M j M F j : h 0 I | finSupp 0 h Base R
105 104 ffnd φ i M j M F j Fn h 0 I | finSupp 0 h
106 77 102 105 offvalfv φ i M j M F i + R f F j = x h 0 I | finSupp 0 h F i x + R F j x
107 98 106 eqtr4d φ i M j M x h 0 I | finSupp 0 h i + R f j x D = F i + R f F j
108 oveq2 f = i + W j D A f = D A i + W j
109 simpr d = D f = i + W j f = i + W j
110 71 adantr d = D f = i + W j x d = x D
111 109 110 fveq12d d = D f = i + W j f x d = i + W j x D
112 111 mpteq2dv d = D f = i + W j x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h i + W j x D
113 112 adantl φ i M j M d = D f = i + W j x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h i + W j x D
114 15 ad2antrr φ i M j M W Grp
115 11 12 114 28 32 grpcld φ i M j M i + W j M
116 77 mptexd φ i M j M x h 0 I | finSupp 0 h i + W j x D V
117 69 113 76 115 116 ovmpod φ i M j M D A i + W j = x h 0 I | finSupp 0 h i + W j x D
118 108 117 sylan9eqr φ i M j M f = i + W j D A f = x h 0 I | finSupp 0 h i + W j x D
119 6 118 115 116 fvmptd2 φ i M j M F i + W j = x h 0 I | finSupp 0 h i + W j x D
120 eqid + R = + R
121 7 11 120 12 28 32 mpladd φ i M j M i + W j = i + R f j
122 121 fveq1d φ i M j M i + W j x D = i + R f j x D
123 122 mpteq2dv φ i M j M x h 0 I | finSupp 0 h i + W j x D = x h 0 I | finSupp 0 h i + R f j x D
124 119 123 eqtrd φ i M j M F i + W j = x h 0 I | finSupp 0 h i + R f j x D
125 7 11 120 12 100 103 mpladd φ i M j M F i + W F j = F i + R f F j
126 107 124 125 3eqtr4d φ i M j M F i + W j = F i + W F j
127 126 anasss φ i M j M F i + W j = F i + W F j
128 simpr φ f = 0 W f = 0 W
129 128 oveq2d φ f = 0 W D A f = D A 0 W
130 4 a1i φ A = d P , f M x h 0 I | finSupp 0 h f x d
131 simplrr φ d = D f = 0 W x h 0 I | finSupp 0 h f = 0 W
132 eqid 0 R = 0 R
133 8 ringgrpd φ R Grp
134 7 27 132 13 5 133 mpl0 φ 0 W = h 0 I | finSupp 0 h × 0 R
135 134 ad2antrr φ d = D f = 0 W x h 0 I | finSupp 0 h 0 W = h 0 I | finSupp 0 h × 0 R
136 131 135 eqtrd φ d = D f = 0 W x h 0 I | finSupp 0 h f = h 0 I | finSupp 0 h × 0 R
137 71 ad2antrl φ d = D f = 0 W x d = x D
138 137 adantr φ d = D f = 0 W x h 0 I | finSupp 0 h x d = x D
139 136 138 fveq12d φ d = D f = 0 W x h 0 I | finSupp 0 h f x d = h 0 I | finSupp 0 h × 0 R x D
140 139 mpteq2dva φ d = D f = 0 W x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h h 0 I | finSupp 0 h × 0 R x D
141 40 a1i φ x h 0 I | finSupp 0 h 0 V
142 5 adantr φ x h 0 I | finSupp 0 h I V
143 52 adantr φ x h 0 I | finSupp 0 h D : I I
144 47 143 fcod φ x h 0 I | finSupp 0 h x D : I 0
145 141 142 144 elmapdd φ x h 0 I | finSupp 0 h x D 0 I
146 39 145 63 elrabd φ x h 0 I | finSupp 0 h x D h 0 I | finSupp 0 h
147 fvex 0 R V
148 147 fvconst2 x D h 0 I | finSupp 0 h h 0 I | finSupp 0 h × 0 R x D = 0 R
149 146 148 syl φ x h 0 I | finSupp 0 h h 0 I | finSupp 0 h × 0 R x D = 0 R
150 149 mpteq2dva φ x h 0 I | finSupp 0 h h 0 I | finSupp 0 h × 0 R x D = x h 0 I | finSupp 0 h 0 R
151 fconstmpt h 0 I | finSupp 0 h × 0 R = x h 0 I | finSupp 0 h 0 R
152 134 151 eqtrdi φ 0 W = x h 0 I | finSupp 0 h 0 R
153 150 152 eqtr4d φ x h 0 I | finSupp 0 h h 0 I | finSupp 0 h × 0 R x D = 0 W
154 153 adantr φ d = D f = 0 W x h 0 I | finSupp 0 h h 0 I | finSupp 0 h × 0 R x D = 0 W
155 140 154 eqtrd φ d = D f = 0 W x h 0 I | finSupp 0 h f x d = 0 W
156 11 13 15 grpidcld φ 0 W M
157 130 155 9 156 156 ovmpod φ D A 0 W = 0 W
158 157 adantr φ f = 0 W D A 0 W = 0 W
159 129 158 eqtrd φ f = 0 W D A f = 0 W
160 6 159 156 156 fvmptd2 φ F 0 W = 0 W
161 11 11 12 12 13 13 16 16 24 127 160 ismhmd φ F W MndHom W