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 5 adantr φ x h 0 I | finSupp 0 h I V
44 40 a1i φ x h 0 I | finSupp 0 h 0 V
45 breq1 h = x finSupp 0 h finSupp 0 x
46 45 elrab x h 0 I | finSupp 0 h x 0 I finSupp 0 x
47 46 bilani φ x h 0 I | finSupp 0 h x 0 I finSupp 0 x
48 47 simpld φ x h 0 I | finSupp 0 h x 0 I
49 43 44 48 elmaprd φ x h 0 I | finSupp 0 h x : I 0
50 49 ad4ant14 φ i M j M x h 0 I | finSupp 0 h x : I 0
51 1 2 symgbasf1o D P D : I 1-1 onto I
52 9 51 syl φ D : I 1-1 onto I
53 f1of D : I 1-1 onto I D : I I
54 52 53 syl φ D : I I
55 54 ad3antrrr φ i M j M x h 0 I | finSupp 0 h D : I I
56 50 55 fcod φ i M j M x h 0 I | finSupp 0 h x D : I 0
57 41 42 56 elmapdd φ i M j M x h 0 I | finSupp 0 h x D 0 I
58 47 simprd φ x h 0 I | finSupp 0 h finSupp 0 x
59 52 adantr φ x h 0 I | finSupp 0 h D : I 1-1 onto I
60 f1of1 D : I 1-1 onto I D : I 1-1 I
61 59 60 syl φ x h 0 I | finSupp 0 h D : I 1-1 I
62 0nn0 0 0
63 62 a1i φ x h 0 I | finSupp 0 h 0 0
64 simpr φ x h 0 I | finSupp 0 h x h 0 I | finSupp 0 h
65 58 61 63 64 fsuppco φ x h 0 I | finSupp 0 h finSupp 0 x D
66 65 ad4ant14 φ i M j M x h 0 I | finSupp 0 h finSupp 0 x D
67 39 57 66 elrabd φ i M j M x h 0 I | finSupp 0 h x D h 0 I | finSupp 0 h
68 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
69 31 35 38 67 68 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
70 oveq2 f = i D A f = D A i
71 4 a1i φ i M j M A = d P , f M x h 0 I | finSupp 0 h f x d
72 simpr d = D f = i f = i
73 coeq2 d = D x d = x D
74 73 adantr d = D f = i x d = x D
75 72 74 fveq12d d = D f = i f x d = i x D
76 75 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
77 76 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
78 9 ad2antrr φ i M j M D P
79 37 a1i φ i M j M h 0 I | finSupp 0 h V
80 79 mptexd φ i M j M x h 0 I | finSupp 0 h i x D V
81 71 77 78 28 80 ovmpod φ i M j M D A i = x h 0 I | finSupp 0 h i x D
82 70 81 sylan9eqr φ i M j M f = i D A f = x h 0 I | finSupp 0 h i x D
83 6 82 28 80 fvmptd2 φ i M j M F i = x h 0 I | finSupp 0 h i x D
84 fvexd φ i M j M x h 0 I | finSupp 0 h i x D V
85 83 84 fvmpt2d φ i M j M x h 0 I | finSupp 0 h F i x = i x D
86 oveq2 f = j D A f = D A j
87 simpr d = D f = j f = j
88 73 adantr d = D f = j x d = x D
89 87 88 fveq12d d = D f = j f x d = j x D
90 89 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
91 90 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
92 79 mptexd φ i M j M x h 0 I | finSupp 0 h j x D V
93 71 91 78 32 92 ovmpod φ i M j M D A j = x h 0 I | finSupp 0 h j x D
94 86 93 sylan9eqr φ i M j M f = j D A f = x h 0 I | finSupp 0 h j x D
95 6 94 32 92 fvmptd2 φ i M j M F j = x h 0 I | finSupp 0 h j x D
96 fvexd φ i M j M x h 0 I | finSupp 0 h j x D V
97 95 96 fvmpt2d φ i M j M x h 0 I | finSupp 0 h F j x = j x D
98 85 97 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
99 69 98 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
100 99 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
101 24 ad2antrr φ i M j M F : M M
102 101 28 ffvelcdmd φ i M j M F i M
103 7 25 11 27 102 mplelf φ i M j M F i : h 0 I | finSupp 0 h Base R
104 103 ffnd φ i M j M F i Fn h 0 I | finSupp 0 h
105 101 32 ffvelcdmd φ i M j M F j M
106 7 25 11 27 105 mplelf φ i M j M F j : h 0 I | finSupp 0 h Base R
107 106 ffnd φ i M j M F j Fn h 0 I | finSupp 0 h
108 79 104 107 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
109 100 108 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
110 oveq2 f = i + W j D A f = D A i + W j
111 simpr d = D f = i + W j f = i + W j
112 73 adantr d = D f = i + W j x d = x D
113 111 112 fveq12d d = D f = i + W j f x d = i + W j x D
114 113 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
115 114 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
116 15 ad2antrr φ i M j M W Grp
117 11 12 116 28 32 grpcld φ i M j M i + W j M
118 79 mptexd φ i M j M x h 0 I | finSupp 0 h i + W j x D V
119 71 115 78 117 118 ovmpod φ i M j M D A i + W j = x h 0 I | finSupp 0 h i + W j x D
120 110 119 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
121 6 120 117 118 fvmptd2 φ i M j M F i + W j = x h 0 I | finSupp 0 h i + W j x D
122 eqid + R = + R
123 7 11 122 12 28 32 mpladd φ i M j M i + W j = i + R f j
124 123 fveq1d φ i M j M i + W j x D = i + R f j x D
125 124 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
126 121 125 eqtrd φ i M j M F i + W j = x h 0 I | finSupp 0 h i + R f j x D
127 7 11 122 12 102 105 mpladd φ i M j M F i + W F j = F i + R f F j
128 109 126 127 3eqtr4d φ i M j M F i + W j = F i + W F j
129 128 anasss φ i M j M F i + W j = F i + W F j
130 simpr φ f = 0 W f = 0 W
131 130 oveq2d φ f = 0 W D A f = D A 0 W
132 4 a1i φ A = d P , f M x h 0 I | finSupp 0 h f x d
133 simplrr φ d = D f = 0 W x h 0 I | finSupp 0 h f = 0 W
134 eqid 0 R = 0 R
135 8 ringgrpd φ R Grp
136 7 27 134 13 5 135 mpl0 φ 0 W = h 0 I | finSupp 0 h × 0 R
137 136 ad2antrr φ d = D f = 0 W x h 0 I | finSupp 0 h 0 W = h 0 I | finSupp 0 h × 0 R
138 133 137 eqtrd φ d = D f = 0 W x h 0 I | finSupp 0 h f = h 0 I | finSupp 0 h × 0 R
139 73 ad2antrl φ d = D f = 0 W x d = x D
140 139 adantr φ d = D f = 0 W x h 0 I | finSupp 0 h x d = x D
141 138 140 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
142 141 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
143 54 adantr φ x h 0 I | finSupp 0 h D : I I
144 49 143 fcod φ x h 0 I | finSupp 0 h x D : I 0
145 44 43 144 elmapdd φ x h 0 I | finSupp 0 h x D 0 I
146 39 145 65 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
152 136 151 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
155 142 154 eqtrd φ d = D f = 0 W x h 0 I | finSupp 0 h f x d = 0 W
156 11 13 grpidcl W Grp 0 W M
157 15 156 syl φ 0 W M
158 132 155 9 157 157 ovmpod φ D A 0 W = 0 W
159 158 adantr φ f = 0 W D A 0 W = 0 W
160 131 159 eqtrd φ f = 0 W D A f = 0 W
161 6 160 157 157 fvmptd2 φ F 0 W = 0 W
162 11 11 12 12 13 13 16 16 24 129 161 ismhmd φ F W MndHom W