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 biimpi x h 0 I | finSupp 0 h x 0 I finSupp 0 x
48 47 adantl φ x h 0 I | finSupp 0 h x 0 I finSupp 0 x
49 48 simpld φ x h 0 I | finSupp 0 h x 0 I
50 43 44 49 elmaprd φ x h 0 I | finSupp 0 h x : I 0
51 50 ad4ant14 φ i M j M x h 0 I | finSupp 0 h x : I 0
52 1 2 symgbasf1o D P D : I 1-1 onto I
53 9 52 syl φ D : I 1-1 onto I
54 f1of D : I 1-1 onto I D : I I
55 53 54 syl φ D : I I
56 55 ad3antrrr φ i M j M x h 0 I | finSupp 0 h D : I I
57 51 56 fcod φ i M j M x h 0 I | finSupp 0 h x D : I 0
58 41 42 57 elmapdd φ i M j M x h 0 I | finSupp 0 h x D 0 I
59 48 simprd φ x h 0 I | finSupp 0 h finSupp 0 x
60 53 adantr φ x h 0 I | finSupp 0 h D : I 1-1 onto I
61 f1of1 D : I 1-1 onto I D : I 1-1 I
62 60 61 syl φ x h 0 I | finSupp 0 h D : I 1-1 I
63 0nn0 0 0
64 63 a1i φ x h 0 I | finSupp 0 h 0 0
65 simpr φ x h 0 I | finSupp 0 h x h 0 I | finSupp 0 h
66 59 62 64 65 fsuppco φ x h 0 I | finSupp 0 h finSupp 0 x D
67 66 ad4ant14 φ i M j M x h 0 I | finSupp 0 h finSupp 0 x D
68 39 58 67 elrabd φ i M j M x h 0 I | finSupp 0 h x D h 0 I | finSupp 0 h
69 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
70 31 35 38 68 69 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
71 oveq2 f = i D A f = D A i
72 4 a1i φ i M j M A = d P , f M x h 0 I | finSupp 0 h f x d
73 simpr d = D f = i f = i
74 coeq2 d = D x d = x D
75 74 adantr d = D f = i x d = x D
76 73 75 fveq12d d = D f = i f x d = i x D
77 76 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
78 77 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
79 9 ad2antrr φ i M j M D P
80 37 a1i φ i M j M h 0 I | finSupp 0 h V
81 80 mptexd φ i M j M x h 0 I | finSupp 0 h i x D V
82 72 78 79 28 81 ovmpod φ i M j M D A i = x h 0 I | finSupp 0 h i x D
83 71 82 sylan9eqr φ i M j M f = i D A f = x h 0 I | finSupp 0 h i x D
84 6 83 28 81 fvmptd2 φ i M j M F i = x h 0 I | finSupp 0 h i x D
85 fvexd φ i M j M x h 0 I | finSupp 0 h i x D V
86 84 85 fvmpt2d φ i M j M x h 0 I | finSupp 0 h F i x = i x D
87 oveq2 f = j D A f = D A j
88 simpr d = D f = j f = j
89 74 adantr d = D f = j x d = x D
90 88 89 fveq12d d = D f = j f x d = j x D
91 90 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
92 91 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
93 80 mptexd φ i M j M x h 0 I | finSupp 0 h j x D V
94 72 92 79 32 93 ovmpod φ i M j M D A j = x h 0 I | finSupp 0 h j x D
95 87 94 sylan9eqr φ i M j M f = j D A f = x h 0 I | finSupp 0 h j x D
96 6 95 32 93 fvmptd2 φ i M j M F j = x h 0 I | finSupp 0 h j x D
97 fvexd φ i M j M x h 0 I | finSupp 0 h j x D V
98 96 97 fvmpt2d φ i M j M x h 0 I | finSupp 0 h F j x = j x D
99 86 98 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
100 70 99 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
101 100 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
102 24 ad2antrr φ i M j M F : M M
103 102 28 ffvelcdmd φ i M j M F i M
104 7 25 11 27 103 mplelf φ i M j M F i : h 0 I | finSupp 0 h Base R
105 104 ffnd φ i M j M F i Fn h 0 I | finSupp 0 h
106 102 32 ffvelcdmd φ i M j M F j M
107 7 25 11 27 106 mplelf φ i M j M F j : h 0 I | finSupp 0 h Base R
108 107 ffnd φ i M j M F j Fn h 0 I | finSupp 0 h
109 80 105 108 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
110 101 109 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
111 oveq2 f = i + W j D A f = D A i + W j
112 simpr d = D f = i + W j f = i + W j
113 74 adantr d = D f = i + W j x d = x D
114 112 113 fveq12d d = D f = i + W j f x d = i + W j x D
115 114 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
116 115 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
117 15 ad2antrr φ i M j M W Grp
118 11 12 117 28 32 grpcld φ i M j M i + W j M
119 80 mptexd φ i M j M x h 0 I | finSupp 0 h i + W j x D V
120 72 116 79 118 119 ovmpod φ i M j M D A i + W j = x h 0 I | finSupp 0 h i + W j x D
121 111 120 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
122 6 121 118 119 fvmptd2 φ i M j M F i + W j = x h 0 I | finSupp 0 h i + W j x D
123 eqid + R = + R
124 7 11 123 12 28 32 mpladd φ i M j M i + W j = i + R f j
125 124 fveq1d φ i M j M i + W j x D = i + R f j x D
126 125 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
127 122 126 eqtrd φ i M j M F i + W j = x h 0 I | finSupp 0 h i + R f j x D
128 7 11 123 12 103 106 mpladd φ i M j M F i + W F j = F i + R f F j
129 110 127 128 3eqtr4d φ i M j M F i + W j = F i + W F j
130 129 anasss φ i M j M F i + W j = F i + W F j
131 simpr φ f = 0 W f = 0 W
132 131 oveq2d φ f = 0 W D A f = D A 0 W
133 4 a1i φ A = d P , f M x h 0 I | finSupp 0 h f x d
134 simplrr φ d = D f = 0 W x h 0 I | finSupp 0 h f = 0 W
135 eqid 0 R = 0 R
136 8 ringgrpd φ R Grp
137 7 27 135 13 5 136 mpl0 φ 0 W = h 0 I | finSupp 0 h × 0 R
138 137 ad2antrr φ d = D f = 0 W x h 0 I | finSupp 0 h 0 W = h 0 I | finSupp 0 h × 0 R
139 134 138 eqtrd φ d = D f = 0 W x h 0 I | finSupp 0 h f = h 0 I | finSupp 0 h × 0 R
140 74 ad2antrl φ d = D f = 0 W x d = x D
141 140 adantr φ d = D f = 0 W x h 0 I | finSupp 0 h x d = x D
142 139 141 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
143 142 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
144 55 adantr φ x h 0 I | finSupp 0 h D : I I
145 50 144 fcod φ x h 0 I | finSupp 0 h x D : I 0
146 44 43 145 elmapdd φ x h 0 I | finSupp 0 h x D 0 I
147 39 146 66 elrabd φ x h 0 I | finSupp 0 h x D h 0 I | finSupp 0 h
148 fvex 0 R V
149 148 fvconst2 x D h 0 I | finSupp 0 h h 0 I | finSupp 0 h × 0 R x D = 0 R
150 147 149 syl φ x h 0 I | finSupp 0 h h 0 I | finSupp 0 h × 0 R x D = 0 R
151 150 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
152 fconstmpt h 0 I | finSupp 0 h × 0 R = x h 0 I | finSupp 0 h 0 R
153 137 152 eqtrdi φ 0 W = x h 0 I | finSupp 0 h 0 R
154 151 153 eqtr4d φ x h 0 I | finSupp 0 h h 0 I | finSupp 0 h × 0 R x D = 0 W
155 154 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
156 143 155 eqtrd φ d = D f = 0 W x h 0 I | finSupp 0 h f x d = 0 W
157 11 13 grpidcl W Grp 0 W M
158 15 157 syl φ 0 W M
159 133 156 9 158 158 ovmpod φ D A 0 W = 0 W
160 159 adantr φ f = 0 W D A 0 W = 0 W
161 132 160 eqtrd φ f = 0 W D A f = 0 W
162 6 161 158 158 fvmptd2 φ F 0 W = 0 W
163 11 11 12 12 13 13 16 16 24 130 162 ismhmd φ F W MndHom W