Metamath Proof Explorer


Theorem gsumzmhm

Description: Apply a group homomorphism to a group sum. (Contributed by Mario Carneiro, 24-Apr-2016) (Revised by AV, 6-Jun-2019)

Ref Expression
Hypotheses gsumzmhm.b ⊢ B = Base G
gsumzmhm.z ⊢ Z = Cntz ⁡ G
gsumzmhm.g ⊢ φ → G ∈ Mnd
gsumzmhm.h ⊢ φ → H ∈ Mnd
gsumzmhm.a ⊢ φ → A ∈ V
gsumzmhm.k ⊢ φ → K ∈ G MndHom H
gsumzmhm.f ⊢ φ → F : A ⟶ B
gsumzmhm.c ⊢ φ → ran ⁡ F ⊆ Z ⁡ ran ⁡ F
gsumzmhm.0 ⊢ 0 ˙ = 0 G
gsumzmhm.w ⊢ φ → finSupp 0 ˙⁡ F
Assertion gsumzmhm ⊢ φ → ∑ H K ∘ F = K ⁡ ∑ G F

Proof

Step Hyp Ref Expression
1 gsumzmhm.b ⊢ B = Base G
2 gsumzmhm.z ⊢ Z = Cntz ⁡ G
3 gsumzmhm.g ⊢ φ → G ∈ Mnd
4 gsumzmhm.h ⊢ φ → H ∈ Mnd
5 gsumzmhm.a ⊢ φ → A ∈ V
6 gsumzmhm.k ⊢ φ → K ∈ G MndHom H
7 gsumzmhm.f ⊢ φ → F : A ⟶ B
8 gsumzmhm.c ⊢ φ → ran ⁡ F ⊆ Z ⁡ ran ⁡ F
9 gsumzmhm.0 ⊢ 0 ˙ = 0 G
10 gsumzmhm.w ⊢ φ → finSupp 0 ˙⁡ F
11 eqid ⊢ 0 H = 0 H
12 11 gsumz ⊢ H ∈ Mnd ∧ A ∈ V → ∑ H k ∈ A 0 H = 0 H
13 4 5 12 syl2anc ⊢ φ → ∑ H k ∈ A 0 H = 0 H
14 13 adantr ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → ∑ H k ∈ A 0 H = 0 H
15 9 11 mhm0 ⊢ K ∈ G MndHom H → K ⁡ 0 ˙ = 0 H
16 6 15 syl ⊢ φ → K ⁡ 0 ˙ = 0 H
17 16 adantr ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → K ⁡ 0 ˙ = 0 H
18 14 17 eqtr4d ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → ∑ H k ∈ A 0 H = K ⁡ 0 ˙
19 1 9 mndidcl ⊢ G ∈ Mnd → 0 ˙ ∈ B
20 3 19 syl ⊢ φ → 0 ˙ ∈ B
21 20 ad2antrr ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ ∧ k ∈ A → 0 ˙ ∈ B
22 9 fvexi ⊢ 0 ˙ ∈ V
23 22 a1i ⊢ φ → 0 ˙ ∈ V
24 7 5 fexd ⊢ φ → F ∈ V
25 suppimacnv ⊢ F ∈ V ∧ 0 ˙ ∈ V → F supp 0 ˙ = F -1 V ∖ 0 ˙
26 24 23 25 syl2anc ⊢ φ → F supp 0 ˙ = F -1 V ∖ 0 ˙
27 ssid ⊢ F -1 V ∖ 0 ˙ ⊆ F -1 V ∖ 0 ˙
28 26 27 eqsstrdi ⊢ φ → F supp 0 ˙ ⊆ F -1 V ∖ 0 ˙
29 7 5 23 28 gsumcllem ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → F = k ∈ A ⟼ 0 ˙
30 eqid ⊢ Base H = Base H
31 1 30 mhmf ⊢ K ∈ G MndHom H → K : B ⟶ Base H
32 6 31 syl ⊢ φ → K : B ⟶ Base H
33 32 feqmptd ⊢ φ → K = x ∈ B ⟼ K ⁡ x
34 33 adantr ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → K = x ∈ B ⟼ K ⁡ x
35 fveq2 ⊢ x = 0 ˙ → K ⁡ x = K ⁡ 0 ˙
36 21 29 34 35 fmptco ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → K ∘ F = k ∈ A ⟼ K ⁡ 0 ˙
37 16 mpteq2dv ⊢ φ → k ∈ A ⟼ K ⁡ 0 ˙ = k ∈ A ⟼ 0 H
38 37 adantr ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → k ∈ A ⟼ K ⁡ 0 ˙ = k ∈ A ⟼ 0 H
39 36 38 eqtrd ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → K ∘ F = k ∈ A ⟼ 0 H
40 39 oveq2d ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → ∑ H K ∘ F = ∑ H k ∈ A 0 H
41 29 oveq2d ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → ∑ G F = ∑ G k ∈ A 0 ˙
42 9 gsumz ⊢ G ∈ Mnd ∧ A ∈ V → ∑ G k ∈ A 0 ˙ = 0 ˙
43 3 5 42 syl2anc ⊢ φ → ∑ G k ∈ A 0 ˙ = 0 ˙
44 43 adantr ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → ∑ G k ∈ A 0 ˙ = 0 ˙
45 41 44 eqtrd ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → ∑ G F = 0 ˙
46 45 fveq2d ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → K ⁡ ∑ G F = K ⁡ 0 ˙
47 18 40 46 3eqtr4d ⊢ φ ∧ F -1 V ∖ 0 ˙ = ∅ → ∑ H K ∘ F = K ⁡ ∑ G F
48 47 ex ⊢ φ → F -1 V ∖ 0 ˙ = ∅ → ∑ H K ∘ F = K ⁡ ∑ G F
49 3 adantr ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → G ∈ Mnd
50 eqid ⊢ + G = + G
51 1 50 mndcl ⊢ G ∈ Mnd ∧ x ∈ B ∧ y ∈ B → x + G y ∈ B
52 51 3expb ⊢ G ∈ Mnd ∧ x ∈ B ∧ y ∈ B → x + G y ∈ B
53 49 52 sylan ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ ∧ x ∈ B ∧ y ∈ B → x + G y ∈ B
54 f1of1 ⊢ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 F -1 V ∖ 0 ˙
55 54 ad2antll ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 F -1 V ∖ 0 ˙
56 cnvimass ⊢ F -1 V ∖ 0 ˙ ⊆ dom ⁡ F
57 7 adantr ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → F : A ⟶ B
58 56 57 fssdm ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → F -1 V ∖ 0 ˙ ⊆ A
59 f1ss ⊢ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 F -1 V ∖ 0 ˙ ∧ F -1 V ∖ 0 ˙ ⊆ A → f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 A
60 55 58 59 syl2anc ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 A
61 f1f ⊢ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 A → f : 1 … F -1 V ∖ 0 ˙ ⟶ A
62 60 61 syl ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → f : 1 … F -1 V ∖ 0 ˙ ⟶ A
63 fco ⊢ F : A ⟶ B ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ A → F ∘ f : 1 … F -1 V ∖ 0 ˙ ⟶ B
64 7 62 63 syl2an2r ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → F ∘ f : 1 … F -1 V ∖ 0 ˙ ⟶ B
65 64 ffvelcdmda ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ ∧ x ∈ 1 … F -1 V ∖ 0 ˙ → F ∘ f ⁡ x ∈ B
66 simprl ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → F -1 V ∖ 0 ˙ ∈ ℕ
67 nnuz ⊢ ℕ = ℤ ≥ 1
68 66 67 eleqtrdi ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → F -1 V ∖ 0 ˙ ∈ ℤ ≥ 1
69 6 adantr ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → K ∈ G MndHom H
70 eqid ⊢ + H = + H
71 1 50 70 mhmlin ⊢ K ∈ G MndHom H ∧ x ∈ B ∧ y ∈ B → K ⁡ x + G y = K ⁡ x + H K ⁡ y
72 71 3expb ⊢ K ∈ G MndHom H ∧ x ∈ B ∧ y ∈ B → K ⁡ x + G y = K ⁡ x + H K ⁡ y
73 69 72 sylan ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ ∧ x ∈ B ∧ y ∈ B → K ⁡ x + G y = K ⁡ x + H K ⁡ y
74 coass ⊢ K ∘ F ∘ f = K ∘ F ∘ f
75 74 fveq1i ⊢ K ∘ F ∘ f ⁡ x = K ∘ F ∘ f ⁡ x
76 fvco3 ⊢ F ∘ f : 1 … F -1 V ∖ 0 ˙ ⟶ B ∧ x ∈ 1 … F -1 V ∖ 0 ˙ → K ∘ F ∘ f ⁡ x = K ⁡ F ∘ f ⁡ x
77 64 76 sylan ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ ∧ x ∈ 1 … F -1 V ∖ 0 ˙ → K ∘ F ∘ f ⁡ x = K ⁡ F ∘ f ⁡ x
78 75 77 eqtr2id ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ ∧ x ∈ 1 … F -1 V ∖ 0 ˙ → K ⁡ F ∘ f ⁡ x = K ∘ F ∘ f ⁡ x
79 53 65 68 73 78 seqhomo ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → K ⁡ seq 1 + G F ∘ f ⁡ F -1 V ∖ 0 ˙ = seq 1 + H K ∘ F ∘ f ⁡ F -1 V ∖ 0 ˙
80 5 adantr ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → A ∈ V
81 8 adantr ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → ran ⁡ F ⊆ Z ⁡ ran ⁡ F
82 28 adantr ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → F supp 0 ˙ ⊆ F -1 V ∖ 0 ˙
83 f1ofo ⊢ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → f : 1 … F -1 V ∖ 0 ˙ ⟶ onto F -1 V ∖ 0 ˙
84 forn ⊢ f : 1 … F -1 V ∖ 0 ˙ ⟶ onto F -1 V ∖ 0 ˙ → ran ⁡ f = F -1 V ∖ 0 ˙
85 83 84 syl ⊢ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → ran ⁡ f = F -1 V ∖ 0 ˙
86 85 ad2antll ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → ran ⁡ f = F -1 V ∖ 0 ˙
87 82 86 sseqtrrd ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → F supp 0 ˙ ⊆ ran ⁡ f
88 eqid ⊢ F ∘ f supp 0 ˙ = F ∘ f supp 0 ˙
89 1 9 50 2 49 80 57 81 66 60 87 88 gsumval3 ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → ∑ G F = seq 1 + G F ∘ f ⁡ F -1 V ∖ 0 ˙
90 89 fveq2d ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → K ⁡ ∑ G F = K ⁡ seq 1 + G F ∘ f ⁡ F -1 V ∖ 0 ˙
91 eqid ⊢ Cntz ⁡ H = Cntz ⁡ H
92 4 adantr ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → H ∈ Mnd
93 fco ⊢ K : B ⟶ Base H ∧ F : A ⟶ B → K ∘ F : A ⟶ Base H
94 32 57 93 syl2an2r ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → K ∘ F : A ⟶ Base H
95 2 91 cntzmhm2 ⊢ K ∈ G MndHom H ∧ ran ⁡ F ⊆ Z ⁡ ran ⁡ F → K ran ⁡ F ⊆ Cntz ⁡ H ⁡ K ran ⁡ F
96 6 81 95 syl2an2r ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → K ran ⁡ F ⊆ Cntz ⁡ H ⁡ K ran ⁡ F
97 rnco2 ⊢ ran ⁡ K ∘ F = K ran ⁡ F
98 97 fveq2i ⊢ Cntz ⁡ H ⁡ ran ⁡ K ∘ F = Cntz ⁡ H ⁡ K ran ⁡ F
99 96 97 98 3sstr4g ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → ran ⁡ K ∘ F ⊆ Cntz ⁡ H ⁡ ran ⁡ K ∘ F
100 eldifi ⊢ x ∈ A ∖ F -1 V ∖ 0 ˙ → x ∈ A
101 fvco3 ⊢ F : A ⟶ B ∧ x ∈ A → K ∘ F ⁡ x = K ⁡ F ⁡ x
102 57 100 101 syl2an ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ ∧ x ∈ A ∖ F -1 V ∖ 0 ˙ → K ∘ F ⁡ x = K ⁡ F ⁡ x
103 22 a1i ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → 0 ˙ ∈ V
104 57 82 80 103 suppssr ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ ∧ x ∈ A ∖ F -1 V ∖ 0 ˙ → F ⁡ x = 0 ˙
105 104 fveq2d ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ ∧ x ∈ A ∖ F -1 V ∖ 0 ˙ → K ⁡ F ⁡ x = K ⁡ 0 ˙
106 16 ad2antrr ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ ∧ x ∈ A ∖ F -1 V ∖ 0 ˙ → K ⁡ 0 ˙ = 0 H
107 102 105 106 3eqtrd ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ ∧ x ∈ A ∖ F -1 V ∖ 0 ˙ → K ∘ F ⁡ x = 0 H
108 94 107 suppss ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → K ∘ F supp 0 H ⊆ F -1 V ∖ 0 ˙
109 108 86 sseqtrrd ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → K ∘ F supp 0 H ⊆ ran ⁡ f
110 eqid ⊢ K ∘ F ∘ f supp 0 H = K ∘ F ∘ f supp 0 H
111 30 11 70 91 92 80 94 99 66 60 109 110 gsumval3 ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → ∑ H K ∘ F = seq 1 + H K ∘ F ∘ f ⁡ F -1 V ∖ 0 ˙
112 79 90 111 3eqtr4rd ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ ∧ f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → ∑ H K ∘ F = K ⁡ ∑ G F
113 112 expr ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ → f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → ∑ H K ∘ F = K ⁡ ∑ G F
114 113 exlimdv ⊢ φ ∧ F -1 V ∖ 0 ˙ ∈ ℕ → ∃ f f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → ∑ H K ∘ F = K ⁡ ∑ G F
115 114 expimpd ⊢ φ → F -1 V ∖ 0 ˙ ∈ ℕ ∧ ∃ f f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙ → ∑ H K ∘ F = K ⁡ ∑ G F
116 10 fsuppimpd ⊢ φ → F supp 0 ˙ ∈ Fin
117 26 116 eqeltrrd ⊢ φ → F -1 V ∖ 0 ˙ ∈ Fin
118 fz1f1o ⊢ F -1 V ∖ 0 ˙ ∈ Fin → F -1 V ∖ 0 ˙ = ∅ ∨ F -1 V ∖ 0 ˙ ∈ ℕ ∧ ∃ f f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙
119 117 118 syl ⊢ φ → F -1 V ∖ 0 ˙ = ∅ ∨ F -1 V ∖ 0 ˙ ∈ ℕ ∧ ∃ f f : 1 … F -1 V ∖ 0 ˙ ⟶ 1-1 onto F -1 V ∖ 0 ˙
120 48 115 119 mpjaod ⊢ φ → ∑ H K ∘ F = K ⁡ ∑ G F