Metamath Proof Explorer


Theorem psrlidm

Description: The identity element of the ring of power series is a left identity. (Contributed by Mario Carneiro, 29-Dec-2014) (Proof shortened by AV, 8-Jul-2019)

Ref Expression
Hypotheses psrring.s 𝑆 = ( 𝐼 mPwSer 𝑅 )
psrring.i ( 𝜑𝐼𝑉 )
psrring.r ( 𝜑𝑅 ∈ Ring )
psr1cl.d 𝐷 = { 𝑓 ∈ ( ℕ0m 𝐼 ) ∣ ( 𝑓 “ ℕ ) ∈ Fin }
psr1cl.z 0 = ( 0g𝑅 )
psr1cl.o 1 = ( 1r𝑅 )
psr1cl.u 𝑈 = ( 𝑥𝐷 ↦ if ( 𝑥 = ( 𝐼 × { 0 } ) , 1 , 0 ) )
psr1cl.b 𝐵 = ( Base ‘ 𝑆 )
psrlidm.t · = ( .r𝑆 )
psrlidm.x ( 𝜑𝑋𝐵 )
Assertion psrlidm ( 𝜑 → ( 𝑈 · 𝑋 ) = 𝑋 )

Proof

Step Hyp Ref Expression
1 psrring.s 𝑆 = ( 𝐼 mPwSer 𝑅 )
2 psrring.i ( 𝜑𝐼𝑉 )
3 psrring.r ( 𝜑𝑅 ∈ Ring )
4 psr1cl.d 𝐷 = { 𝑓 ∈ ( ℕ0m 𝐼 ) ∣ ( 𝑓 “ ℕ ) ∈ Fin }
5 psr1cl.z 0 = ( 0g𝑅 )
6 psr1cl.o 1 = ( 1r𝑅 )
7 psr1cl.u 𝑈 = ( 𝑥𝐷 ↦ if ( 𝑥 = ( 𝐼 × { 0 } ) , 1 , 0 ) )
8 psr1cl.b 𝐵 = ( Base ‘ 𝑆 )
9 psrlidm.t · = ( .r𝑆 )
10 psrlidm.x ( 𝜑𝑋𝐵 )
11 eqid ( Base ‘ 𝑅 ) = ( Base ‘ 𝑅 )
12 1 2 3 4 5 6 7 8 psr1cl ( 𝜑𝑈𝐵 )
13 1 8 9 3 12 10 psrmulcl ( 𝜑 → ( 𝑈 · 𝑋 ) ∈ 𝐵 )
14 1 11 4 8 13 psrelbas ( 𝜑 → ( 𝑈 · 𝑋 ) : 𝐷 ⟶ ( Base ‘ 𝑅 ) )
15 14 ffnd ( 𝜑 → ( 𝑈 · 𝑋 ) Fn 𝐷 )
16 1 11 4 8 10 psrelbas ( 𝜑𝑋 : 𝐷 ⟶ ( Base ‘ 𝑅 ) )
17 16 ffnd ( 𝜑𝑋 Fn 𝐷 )
18 eqid ( .r𝑅 ) = ( .r𝑅 )
19 12 adantr ( ( 𝜑𝑦𝐷 ) → 𝑈𝐵 )
20 10 adantr ( ( 𝜑𝑦𝐷 ) → 𝑋𝐵 )
21 simpr ( ( 𝜑𝑦𝐷 ) → 𝑦𝐷 )
22 1 8 18 9 4 19 20 21 psrmulval ( ( 𝜑𝑦𝐷 ) → ( ( 𝑈 · 𝑋 ) ‘ 𝑦 ) = ( 𝑅 Σg ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ) )
23 breq1 ( 𝑔 = ( 𝐼 × { 0 } ) → ( 𝑔r𝑦 ↔ ( 𝐼 × { 0 } ) ∘r𝑦 ) )
24 fconstmpt ( 𝐼 × { 0 } ) = ( 𝑥𝐼 ↦ 0 )
25 4 fczpsrbag ( 𝐼𝑉 → ( 𝑥𝐼 ↦ 0 ) ∈ 𝐷 )
26 2 25 syl ( 𝜑 → ( 𝑥𝐼 ↦ 0 ) ∈ 𝐷 )
27 24 26 eqeltrid ( 𝜑 → ( 𝐼 × { 0 } ) ∈ 𝐷 )
28 27 adantr ( ( 𝜑𝑦𝐷 ) → ( 𝐼 × { 0 } ) ∈ 𝐷 )
29 4 psrbagf ( 𝑦𝐷𝑦 : 𝐼 ⟶ ℕ0 )
30 29 adantl ( ( 𝜑𝑦𝐷 ) → 𝑦 : 𝐼 ⟶ ℕ0 )
31 30 ffvelrnda ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑥𝐼 ) → ( 𝑦𝑥 ) ∈ ℕ0 )
32 31 nn0ge0d ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑥𝐼 ) → 0 ≤ ( 𝑦𝑥 ) )
33 32 ralrimiva ( ( 𝜑𝑦𝐷 ) → ∀ 𝑥𝐼 0 ≤ ( 𝑦𝑥 ) )
34 0nn0 0 ∈ ℕ0
35 34 fconst6 ( 𝐼 × { 0 } ) : 𝐼 ⟶ ℕ0
36 ffn ( ( 𝐼 × { 0 } ) : 𝐼 ⟶ ℕ0 → ( 𝐼 × { 0 } ) Fn 𝐼 )
37 35 36 mp1i ( ( 𝜑𝑦𝐷 ) → ( 𝐼 × { 0 } ) Fn 𝐼 )
38 30 ffnd ( ( 𝜑𝑦𝐷 ) → 𝑦 Fn 𝐼 )
39 2 adantr ( ( 𝜑𝑦𝐷 ) → 𝐼𝑉 )
40 inidm ( 𝐼𝐼 ) = 𝐼
41 34 a1i ( ( 𝜑𝑦𝐷 ) → 0 ∈ ℕ0 )
42 fvconst2g ( ( 0 ∈ ℕ0𝑥𝐼 ) → ( ( 𝐼 × { 0 } ) ‘ 𝑥 ) = 0 )
43 41 42 sylan ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑥𝐼 ) → ( ( 𝐼 × { 0 } ) ‘ 𝑥 ) = 0 )
44 eqidd ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑥𝐼 ) → ( 𝑦𝑥 ) = ( 𝑦𝑥 ) )
45 37 38 39 39 40 43 44 ofrfval ( ( 𝜑𝑦𝐷 ) → ( ( 𝐼 × { 0 } ) ∘r𝑦 ↔ ∀ 𝑥𝐼 0 ≤ ( 𝑦𝑥 ) ) )
46 33 45 mpbird ( ( 𝜑𝑦𝐷 ) → ( 𝐼 × { 0 } ) ∘r𝑦 )
47 23 28 46 elrabd ( ( 𝜑𝑦𝐷 ) → ( 𝐼 × { 0 } ) ∈ { 𝑔𝐷𝑔r𝑦 } )
48 47 snssd ( ( 𝜑𝑦𝐷 ) → { ( 𝐼 × { 0 } ) } ⊆ { 𝑔𝐷𝑔r𝑦 } )
49 48 resmptd ( ( 𝜑𝑦𝐷 ) → ( ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ↾ { ( 𝐼 × { 0 } ) } ) = ( 𝑧 ∈ { ( 𝐼 × { 0 } ) } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) )
50 49 oveq2d ( ( 𝜑𝑦𝐷 ) → ( 𝑅 Σg ( ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ↾ { ( 𝐼 × { 0 } ) } ) ) = ( 𝑅 Σg ( 𝑧 ∈ { ( 𝐼 × { 0 } ) } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ) )
51 ringcmn ( 𝑅 ∈ Ring → 𝑅 ∈ CMnd )
52 3 51 syl ( 𝜑𝑅 ∈ CMnd )
53 52 adantr ( ( 𝜑𝑦𝐷 ) → 𝑅 ∈ CMnd )
54 ovex ( ℕ0m 𝐼 ) ∈ V
55 4 54 rab2ex { 𝑔𝐷𝑔r𝑦 } ∈ V
56 55 a1i ( ( 𝜑𝑦𝐷 ) → { 𝑔𝐷𝑔r𝑦 } ∈ V )
57 3 ad2antrr ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → 𝑅 ∈ Ring )
58 simpr ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } )
59 breq1 ( 𝑔 = 𝑧 → ( 𝑔r𝑦𝑧r𝑦 ) )
60 59 elrab ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↔ ( 𝑧𝐷𝑧r𝑦 ) )
61 58 60 sylib ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → ( 𝑧𝐷𝑧r𝑦 ) )
62 61 simpld ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → 𝑧𝐷 )
63 1 11 4 8 19 psrelbas ( ( 𝜑𝑦𝐷 ) → 𝑈 : 𝐷 ⟶ ( Base ‘ 𝑅 ) )
64 63 ffvelrnda ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧𝐷 ) → ( 𝑈𝑧 ) ∈ ( Base ‘ 𝑅 ) )
65 62 64 syldan ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → ( 𝑈𝑧 ) ∈ ( Base ‘ 𝑅 ) )
66 16 ad2antrr ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → 𝑋 : 𝐷 ⟶ ( Base ‘ 𝑅 ) )
67 21 adantr ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → 𝑦𝐷 )
68 4 psrbagf ( 𝑧𝐷𝑧 : 𝐼 ⟶ ℕ0 )
69 62 68 syl ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → 𝑧 : 𝐼 ⟶ ℕ0 )
70 61 simprd ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → 𝑧r𝑦 )
71 4 psrbagcon ( ( 𝑦𝐷𝑧 : 𝐼 ⟶ ℕ0𝑧r𝑦 ) → ( ( 𝑦f𝑧 ) ∈ 𝐷 ∧ ( 𝑦f𝑧 ) ∘r𝑦 ) )
72 67 69 70 71 syl3anc ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → ( ( 𝑦f𝑧 ) ∈ 𝐷 ∧ ( 𝑦f𝑧 ) ∘r𝑦 ) )
73 72 simpld ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → ( 𝑦f𝑧 ) ∈ 𝐷 )
74 66 73 ffvelrnd ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ∈ ( Base ‘ 𝑅 ) )
75 11 18 ringcl ( ( 𝑅 ∈ Ring ∧ ( 𝑈𝑧 ) ∈ ( Base ‘ 𝑅 ) ∧ ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ∈ ( Base ‘ 𝑅 ) ) → ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ∈ ( Base ‘ 𝑅 ) )
76 57 65 74 75 syl3anc ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ) → ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ∈ ( Base ‘ 𝑅 ) )
77 76 fmpttd ( ( 𝜑𝑦𝐷 ) → ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) : { 𝑔𝐷𝑔r𝑦 } ⟶ ( Base ‘ 𝑅 ) )
78 eldifi ( 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) → 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } )
79 78 61 sylan2 ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) ) → ( 𝑧𝐷𝑧r𝑦 ) )
80 79 simpld ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) ) → 𝑧𝐷 )
81 eqeq1 ( 𝑥 = 𝑧 → ( 𝑥 = ( 𝐼 × { 0 } ) ↔ 𝑧 = ( 𝐼 × { 0 } ) ) )
82 81 ifbid ( 𝑥 = 𝑧 → if ( 𝑥 = ( 𝐼 × { 0 } ) , 1 , 0 ) = if ( 𝑧 = ( 𝐼 × { 0 } ) , 1 , 0 ) )
83 6 fvexi 1 ∈ V
84 5 fvexi 0 ∈ V
85 83 84 ifex if ( 𝑧 = ( 𝐼 × { 0 } ) , 1 , 0 ) ∈ V
86 82 7 85 fvmpt ( 𝑧𝐷 → ( 𝑈𝑧 ) = if ( 𝑧 = ( 𝐼 × { 0 } ) , 1 , 0 ) )
87 80 86 syl ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) ) → ( 𝑈𝑧 ) = if ( 𝑧 = ( 𝐼 × { 0 } ) , 1 , 0 ) )
88 eldifn ( 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) → ¬ 𝑧 ∈ { ( 𝐼 × { 0 } ) } )
89 88 adantl ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) ) → ¬ 𝑧 ∈ { ( 𝐼 × { 0 } ) } )
90 velsn ( 𝑧 ∈ { ( 𝐼 × { 0 } ) } ↔ 𝑧 = ( 𝐼 × { 0 } ) )
91 89 90 sylnib ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) ) → ¬ 𝑧 = ( 𝐼 × { 0 } ) )
92 91 iffalsed ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) ) → if ( 𝑧 = ( 𝐼 × { 0 } ) , 1 , 0 ) = 0 )
93 87 92 eqtrd ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) ) → ( 𝑈𝑧 ) = 0 )
94 93 oveq1d ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) ) → ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) = ( 0 ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) )
95 3 ad2antrr ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) ) → 𝑅 ∈ Ring )
96 78 74 sylan2 ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) ) → ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ∈ ( Base ‘ 𝑅 ) )
97 11 18 5 ringlz ( ( 𝑅 ∈ Ring ∧ ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ∈ ( Base ‘ 𝑅 ) ) → ( 0 ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) = 0 )
98 95 96 97 syl2anc ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) ) → ( 0 ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) = 0 )
99 94 98 eqtrd ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ( { 𝑔𝐷𝑔r𝑦 } ∖ { ( 𝐼 × { 0 } ) } ) ) → ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) = 0 )
100 99 56 suppss2 ( ( 𝜑𝑦𝐷 ) → ( ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) supp 0 ) ⊆ { ( 𝐼 × { 0 } ) } )
101 4 54 rabex2 𝐷 ∈ V
102 101 mptrabex ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ∈ V
103 102 a1i ( ( 𝜑𝑦𝐷 ) → ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ∈ V )
104 funmpt Fun ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) )
105 104 a1i ( ( 𝜑𝑦𝐷 ) → Fun ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) )
106 84 a1i ( ( 𝜑𝑦𝐷 ) → 0 ∈ V )
107 snfi { ( 𝐼 × { 0 } ) } ∈ Fin
108 107 a1i ( ( 𝜑𝑦𝐷 ) → { ( 𝐼 × { 0 } ) } ∈ Fin )
109 suppssfifsupp ( ( ( ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ∈ V ∧ Fun ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ∧ 0 ∈ V ) ∧ ( { ( 𝐼 × { 0 } ) } ∈ Fin ∧ ( ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) supp 0 ) ⊆ { ( 𝐼 × { 0 } ) } ) ) → ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) finSupp 0 )
110 103 105 106 108 100 109 syl32anc ( ( 𝜑𝑦𝐷 ) → ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) finSupp 0 )
111 11 5 53 56 77 100 110 gsumres ( ( 𝜑𝑦𝐷 ) → ( 𝑅 Σg ( ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ↾ { ( 𝐼 × { 0 } ) } ) ) = ( 𝑅 Σg ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ) )
112 3 adantr ( ( 𝜑𝑦𝐷 ) → 𝑅 ∈ Ring )
113 ringmnd ( 𝑅 ∈ Ring → 𝑅 ∈ Mnd )
114 112 113 syl ( ( 𝜑𝑦𝐷 ) → 𝑅 ∈ Mnd )
115 iftrue ( 𝑥 = ( 𝐼 × { 0 } ) → if ( 𝑥 = ( 𝐼 × { 0 } ) , 1 , 0 ) = 1 )
116 115 7 83 fvmpt ( ( 𝐼 × { 0 } ) ∈ 𝐷 → ( 𝑈 ‘ ( 𝐼 × { 0 } ) ) = 1 )
117 28 116 syl ( ( 𝜑𝑦𝐷 ) → ( 𝑈 ‘ ( 𝐼 × { 0 } ) ) = 1 )
118 nn0cn ( 𝑧 ∈ ℕ0𝑧 ∈ ℂ )
119 118 subid1d ( 𝑧 ∈ ℕ0 → ( 𝑧 − 0 ) = 𝑧 )
120 119 adantl ( ( ( 𝜑𝑦𝐷 ) ∧ 𝑧 ∈ ℕ0 ) → ( 𝑧 − 0 ) = 𝑧 )
121 39 30 41 120 caofid0r ( ( 𝜑𝑦𝐷 ) → ( 𝑦f − ( 𝐼 × { 0 } ) ) = 𝑦 )
122 121 fveq2d ( ( 𝜑𝑦𝐷 ) → ( 𝑋 ‘ ( 𝑦f − ( 𝐼 × { 0 } ) ) ) = ( 𝑋𝑦 ) )
123 117 122 oveq12d ( ( 𝜑𝑦𝐷 ) → ( ( 𝑈 ‘ ( 𝐼 × { 0 } ) ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f − ( 𝐼 × { 0 } ) ) ) ) = ( 1 ( .r𝑅 ) ( 𝑋𝑦 ) ) )
124 16 ffvelrnda ( ( 𝜑𝑦𝐷 ) → ( 𝑋𝑦 ) ∈ ( Base ‘ 𝑅 ) )
125 11 18 6 ringlidm ( ( 𝑅 ∈ Ring ∧ ( 𝑋𝑦 ) ∈ ( Base ‘ 𝑅 ) ) → ( 1 ( .r𝑅 ) ( 𝑋𝑦 ) ) = ( 𝑋𝑦 ) )
126 112 124 125 syl2anc ( ( 𝜑𝑦𝐷 ) → ( 1 ( .r𝑅 ) ( 𝑋𝑦 ) ) = ( 𝑋𝑦 ) )
127 123 126 eqtrd ( ( 𝜑𝑦𝐷 ) → ( ( 𝑈 ‘ ( 𝐼 × { 0 } ) ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f − ( 𝐼 × { 0 } ) ) ) ) = ( 𝑋𝑦 ) )
128 127 124 eqeltrd ( ( 𝜑𝑦𝐷 ) → ( ( 𝑈 ‘ ( 𝐼 × { 0 } ) ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f − ( 𝐼 × { 0 } ) ) ) ) ∈ ( Base ‘ 𝑅 ) )
129 fveq2 ( 𝑧 = ( 𝐼 × { 0 } ) → ( 𝑈𝑧 ) = ( 𝑈 ‘ ( 𝐼 × { 0 } ) ) )
130 oveq2 ( 𝑧 = ( 𝐼 × { 0 } ) → ( 𝑦f𝑧 ) = ( 𝑦f − ( 𝐼 × { 0 } ) ) )
131 130 fveq2d ( 𝑧 = ( 𝐼 × { 0 } ) → ( 𝑋 ‘ ( 𝑦f𝑧 ) ) = ( 𝑋 ‘ ( 𝑦f − ( 𝐼 × { 0 } ) ) ) )
132 129 131 oveq12d ( 𝑧 = ( 𝐼 × { 0 } ) → ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) = ( ( 𝑈 ‘ ( 𝐼 × { 0 } ) ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f − ( 𝐼 × { 0 } ) ) ) ) )
133 11 132 gsumsn ( ( 𝑅 ∈ Mnd ∧ ( 𝐼 × { 0 } ) ∈ 𝐷 ∧ ( ( 𝑈 ‘ ( 𝐼 × { 0 } ) ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f − ( 𝐼 × { 0 } ) ) ) ) ∈ ( Base ‘ 𝑅 ) ) → ( 𝑅 Σg ( 𝑧 ∈ { ( 𝐼 × { 0 } ) } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ) = ( ( 𝑈 ‘ ( 𝐼 × { 0 } ) ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f − ( 𝐼 × { 0 } ) ) ) ) )
134 114 28 128 133 syl3anc ( ( 𝜑𝑦𝐷 ) → ( 𝑅 Σg ( 𝑧 ∈ { ( 𝐼 × { 0 } ) } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ) = ( ( 𝑈 ‘ ( 𝐼 × { 0 } ) ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f − ( 𝐼 × { 0 } ) ) ) ) )
135 50 111 134 3eqtr3d ( ( 𝜑𝑦𝐷 ) → ( 𝑅 Σg ( 𝑧 ∈ { 𝑔𝐷𝑔r𝑦 } ↦ ( ( 𝑈𝑧 ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f𝑧 ) ) ) ) ) = ( ( 𝑈 ‘ ( 𝐼 × { 0 } ) ) ( .r𝑅 ) ( 𝑋 ‘ ( 𝑦f − ( 𝐼 × { 0 } ) ) ) ) )
136 22 135 127 3eqtrd ( ( 𝜑𝑦𝐷 ) → ( ( 𝑈 · 𝑋 ) ‘ 𝑦 ) = ( 𝑋𝑦 ) )
137 15 17 136 eqfnfvd ( 𝜑 → ( 𝑈 · 𝑋 ) = 𝑋 )