Metamath Proof Explorer


Theorem bj-finsumval0

Description: Value of a finite sum. (Contributed by BJ, 9-Jun-2019) (Proof shortened by AV, 5-May-2021)

Ref Expression
Hypotheses bj-finsumval0.1 ⊢ φ → A ∈ CMnd
bj-finsumval0.2 ⊢ φ → I ∈ Fin
bj-finsumval0.3 ⊢ φ → B : I ⟶ Base A
Assertion bj-finsumval0 ⊢ φ → A FinSum B = ι s | ∃ m ∈ ℕ 0 ∃ f f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I

Proof

Step Hyp Ref Expression
1 bj-finsumval0.1 ⊢ φ → A ∈ CMnd
2 bj-finsumval0.2 ⊢ φ → I ∈ Fin
3 bj-finsumval0.3 ⊢ φ → B : I ⟶ Base A
4 df-ov ⊢ A FinSum B = FinSum ⁡ A B
5 df-bj-finsum ⊢ FinSum = x ∈ y z | y ∈ CMnd ∧ ∃ t ∈ Fin z : t ⟶ Base y ⟼ ι s | ∃ m ∈ ℕ 0 ∃ f f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m
6 simpr ⊢ φ ∧ x = A B → x = A B
7 6 fveq2d ⊢ φ ∧ x = A B → 1 st ⁡ x = 1 st ⁡ A B
8 1 adantr ⊢ φ ∧ x = A B → A ∈ CMnd
9 3 2 fexd ⊢ φ → B ∈ V
10 9 adantr ⊢ φ ∧ x = A B → B ∈ V
11 op1stg ⊢ A ∈ CMnd ∧ B ∈ V → 1 st ⁡ A B = A
12 8 10 11 syl2anc ⊢ φ ∧ x = A B → 1 st ⁡ A B = A
13 7 12 eqtrd ⊢ φ ∧ x = A B → 1 st ⁡ x = A
14 6 fveq2d ⊢ φ ∧ x = A B → 2 nd ⁡ x = 2 nd ⁡ A B
15 op2ndg ⊢ A ∈ CMnd ∧ B ∈ V → 2 nd ⁡ A B = B
16 8 10 15 syl2anc ⊢ φ ∧ x = A B → 2 nd ⁡ A B = B
17 14 16 eqtrd ⊢ φ ∧ x = A B → 2 nd ⁡ x = B
18 17 dmeqd ⊢ φ ∧ x = A B → dom ⁡ 2 nd ⁡ x = dom ⁡ B
19 3 fdmd ⊢ φ → dom ⁡ B = I
20 19 adantr ⊢ φ ∧ x = A B → dom ⁡ B = I
21 18 20 eqtrd ⊢ φ ∧ x = A B → dom ⁡ 2 nd ⁡ x = I
22 f1oeq3 ⊢ dom ⁡ 2 nd ⁡ x = I → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ↔ f : 1 … m ⟶ 1-1 onto I
23 22 biimpd ⊢ dom ⁡ 2 nd ⁡ x = I → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x → f : 1 … m ⟶ 1-1 onto I
24 23 ad2antll ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x → f : 1 … m ⟶ 1-1 onto I
25 24 adantrd ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m → f : 1 … m ⟶ 1-1 onto I
26 25 adantr ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m → f : 1 … m ⟶ 1-1 onto I
27 eqidd ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → 1 = 1
28 simprl ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → 1 st ⁡ x = A
29 28 fveq2d ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → + 1 st ⁡ x = + A
30 29 adantrr ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → + 1 st ⁡ x = + A
31 simprrl ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → 2 nd ⁡ x = B
32 31 adantr ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ n ∈ ℕ → 2 nd ⁡ x = B
33 32 fveq1d ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ n ∈ ℕ → 2 nd ⁡ x ⁡ f ⁡ n = B ⁡ f ⁡ n
34 33 mpteq2dva ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n = n ∈ ℕ ⟼ B ⁡ f ⁡ n
35 34 adantrr ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n = n ∈ ℕ ⟼ B ⁡ f ⁡ n
36 27 30 35 seqeq123d ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n
37 simprr ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → dom ⁡ 2 nd ⁡ x = I
38 37 anim1ci ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → m ∈ ℕ 0 ∧ dom ⁡ 2 nd ⁡ x = I
39 hashfz1 ⊢ m ∈ ℕ 0 → 1 … m = m
40 39 eqcomd ⊢ m ∈ ℕ 0 → m = 1 … m
41 40 ad2antrl ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ m ∈ ℕ 0 ∧ dom ⁡ 2 nd ⁡ x = I → m = 1 … m
42 fzfid ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ m ∈ ℕ 0 ∧ dom ⁡ 2 nd ⁡ x = I → 1 … m ∈ Fin
43 19.8a ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x → ∃ f f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x
44 43 adantr ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ m ∈ ℕ 0 ∧ dom ⁡ 2 nd ⁡ x = I → ∃ f f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x
45 hasheqf1oi ⊢ 1 … m ∈ Fin → ∃ f f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x → 1 … m = dom ⁡ 2 nd ⁡ x
46 42 44 45 sylc ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ m ∈ ℕ 0 ∧ dom ⁡ 2 nd ⁡ x = I → 1 … m = dom ⁡ 2 nd ⁡ x
47 simprr ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ m ∈ ℕ 0 ∧ dom ⁡ 2 nd ⁡ x = I → dom ⁡ 2 nd ⁡ x = I
48 47 fveq2d ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ m ∈ ℕ 0 ∧ dom ⁡ 2 nd ⁡ x = I → dom ⁡ 2 nd ⁡ x = I
49 41 46 48 3eqtrd ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ m ∈ ℕ 0 ∧ dom ⁡ 2 nd ⁡ x = I → m = I
50 38 49 sylan2 ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → m = I
51 36 50 fveq12d ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
52 51 eqeq2d ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m ↔ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
53 52 biimpd ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m → s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
54 53 impancom ⊢ f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m → 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
55 54 com12 ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m → s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
56 26 55 jcad ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m → f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
57 22 biimprd ⊢ dom ⁡ 2 nd ⁡ x = I → f : 1 … m ⟶ 1-1 onto I → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x
58 57 ad2antll ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → f : 1 … m ⟶ 1-1 onto I → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x
59 58 adantr ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → f : 1 … m ⟶ 1-1 onto I → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x
60 59 adantrd ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x
61 eqidd ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → 1 = 1
62 simpl ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → 1 st ⁡ x = A
63 tru ⊢ ⊤
64 62 63 jctir ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → 1 st ⁡ x = A ∧ ⊤
65 64 ad2antrl ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → 1 st ⁡ x = A ∧ ⊤
66 simpl ⊢ 1 st ⁡ x = A ∧ ⊤ → 1 st ⁡ x = A
67 66 eqcomd ⊢ 1 st ⁡ x = A ∧ ⊤ → A = 1 st ⁡ x
68 65 67 syl ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → A = 1 st ⁡ x
69 68 fveq2d ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → + A = + 1 st ⁡ x
70 simpl ⊢ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → 2 nd ⁡ x = B
71 70 eqcomd ⊢ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → B = 2 nd ⁡ x
72 71 ad2antll ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → B = 2 nd ⁡ x
73 72 adantr ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ n ∈ ℕ → B = 2 nd ⁡ x
74 73 fveq1d ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ n ∈ ℕ → B ⁡ f ⁡ n = 2 nd ⁡ x ⁡ f ⁡ n
75 74 adantlrr ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 ∧ n ∈ ℕ → B ⁡ f ⁡ n = 2 nd ⁡ x ⁡ f ⁡ n
76 75 mpteq2dva ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → n ∈ ℕ ⟼ B ⁡ f ⁡ n = n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n
77 61 69 76 seqeq123d ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n
78 59 impcom ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x
79 simprr ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → m ∈ ℕ 0
80 37 ad2antrl ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → dom ⁡ 2 nd ⁡ x = I
81 78 79 80 49 syl12anc ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → m = I
82 81 eqcomd ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → I = m
83 77 82 fveq12d ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m
84 83 eqeq2d ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I ↔ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m
85 84 biimpd ⊢ f : 1 … m ⟶ 1-1 onto I ∧ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I → s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m
86 85 impancom ⊢ f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I → 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m
87 86 com12 ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I → s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m
88 60 87 jcad ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m
89 56 88 impbid ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I ∧ m ∈ ℕ 0 → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m ↔ f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
90 89 ex ⊢ 1 st ⁡ x = A ∧ 2 nd ⁡ x = B ∧ dom ⁡ 2 nd ⁡ x = I → m ∈ ℕ 0 → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m ↔ f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
91 13 17 21 90 syl12anc ⊢ φ ∧ x = A B → m ∈ ℕ 0 → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m ↔ f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
92 91 imp ⊢ φ ∧ x = A B ∧ m ∈ ℕ 0 → f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m ↔ f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
93 92 exbidv ⊢ φ ∧ x = A B ∧ m ∈ ℕ 0 → ∃ f f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m ↔ ∃ f f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
94 93 rexbidva ⊢ φ ∧ x = A B → ∃ m ∈ ℕ 0 ∃ f f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m ↔ ∃ m ∈ ℕ 0 ∃ f f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
95 94 iotabidv ⊢ φ ∧ x = A B → ι s | ∃ m ∈ ℕ 0 ∃ f f : 1 … m ⟶ 1-1 onto dom ⁡ 2 nd ⁡ x ∧ s = seq 1 + 1 st ⁡ x n ∈ ℕ ⟼ 2 nd ⁡ x ⁡ f ⁡ n ⁡ m = ι s | ∃ m ∈ ℕ 0 ∃ f f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
96 eleq1 ⊢ t = I → t ∈ Fin ↔ I ∈ Fin
97 feq2 ⊢ t = I → B : t ⟶ Base A ↔ B : I ⟶ Base A
98 96 97 anbi12d ⊢ t = I → t ∈ Fin ∧ B : t ⟶ Base A ↔ I ∈ Fin ∧ B : I ⟶ Base A
99 98 ceqsexgv ⊢ I ∈ Fin → ∃ t t = I ∧ t ∈ Fin ∧ B : t ⟶ Base A ↔ I ∈ Fin ∧ B : I ⟶ Base A
100 2 99 syl ⊢ φ → ∃ t t = I ∧ t ∈ Fin ∧ B : t ⟶ Base A ↔ I ∈ Fin ∧ B : I ⟶ Base A
101 2 3 100 mpbir2and ⊢ φ → ∃ t t = I ∧ t ∈ Fin ∧ B : t ⟶ Base A
102 exsimpr ⊢ ∃ t t = I ∧ t ∈ Fin ∧ B : t ⟶ Base A → ∃ t t ∈ Fin ∧ B : t ⟶ Base A
103 101 102 syl ⊢ φ → ∃ t t ∈ Fin ∧ B : t ⟶ Base A
104 df-rex ⊢ ∃ t ∈ Fin B : t ⟶ Base A ↔ ∃ t t ∈ Fin ∧ B : t ⟶ Base A
105 103 104 sylibr ⊢ φ → ∃ t ∈ Fin B : t ⟶ Base A
106 eleq1 ⊢ y = A → y ∈ CMnd ↔ A ∈ CMnd
107 fveq2 ⊢ y = A → Base y = Base A
108 107 feq3d ⊢ y = A → z : t ⟶ Base y ↔ z : t ⟶ Base A
109 108 rexbidv ⊢ y = A → ∃ t ∈ Fin z : t ⟶ Base y ↔ ∃ t ∈ Fin z : t ⟶ Base A
110 106 109 anbi12d ⊢ y = A → y ∈ CMnd ∧ ∃ t ∈ Fin z : t ⟶ Base y ↔ A ∈ CMnd ∧ ∃ t ∈ Fin z : t ⟶ Base A
111 feq1 ⊢ z = B → z : t ⟶ Base A ↔ B : t ⟶ Base A
112 111 rexbidv ⊢ z = B → ∃ t ∈ Fin z : t ⟶ Base A ↔ ∃ t ∈ Fin B : t ⟶ Base A
113 112 anbi2d ⊢ z = B → A ∈ CMnd ∧ ∃ t ∈ Fin z : t ⟶ Base A ↔ A ∈ CMnd ∧ ∃ t ∈ Fin B : t ⟶ Base A
114 110 113 opelopabg ⊢ A ∈ CMnd ∧ B ∈ V → A B ∈ y z | y ∈ CMnd ∧ ∃ t ∈ Fin z : t ⟶ Base y ↔ A ∈ CMnd ∧ ∃ t ∈ Fin B : t ⟶ Base A
115 1 9 114 syl2anc ⊢ φ → A B ∈ y z | y ∈ CMnd ∧ ∃ t ∈ Fin z : t ⟶ Base y ↔ A ∈ CMnd ∧ ∃ t ∈ Fin B : t ⟶ Base A
116 1 105 115 mpbir2and ⊢ φ → A B ∈ y z | y ∈ CMnd ∧ ∃ t ∈ Fin z : t ⟶ Base y
117 iotaex ⊢ ι s | ∃ m ∈ ℕ 0 ∃ f f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I ∈ V
118 117 a1i ⊢ φ → ι s | ∃ m ∈ ℕ 0 ∃ f f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I ∈ V
119 5 95 116 118 fvmptd2 ⊢ φ → FinSum ⁡ A B = ι s | ∃ m ∈ ℕ 0 ∃ f f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I
120 4 119 eqtrid ⊢ φ → A FinSum B = ι s | ∃ m ∈ ℕ 0 ∃ f f : 1 … m ⟶ 1-1 onto I ∧ s = seq 1 + A n ∈ ℕ ⟼ B ⁡ f ⁡ n ⁡ I