Metamath Proof Explorer


Theorem ruclem8

Description: Lemma for ruc . The intervals of the G sequence are all nonempty. (Contributed by Mario Carneiro, 28-May-2014)

Ref Expression
Hypotheses ruc.1 ( 𝜑𝐹 : ℕ ⟶ ℝ )
ruc.2 ( 𝜑𝐷 = ( 𝑥 ∈ ( ℝ × ℝ ) , 𝑦 ∈ ℝ ↦ ( ( ( 1st𝑥 ) + ( 2nd𝑥 ) ) / 2 ) / 𝑚 if ( 𝑚 < 𝑦 , ⟨ ( 1st𝑥 ) , 𝑚 ⟩ , ⟨ ( ( 𝑚 + ( 2nd𝑥 ) ) / 2 ) , ( 2nd𝑥 ) ⟩ ) ) )
ruc.4 𝐶 = ( { ⟨ 0 , ⟨ 0 , 1 ⟩ ⟩ } ∪ 𝐹 )
ruc.5 𝐺 = seq 0 ( 𝐷 , 𝐶 )
Assertion ruclem8 ( ( 𝜑𝑁 ∈ ℕ0 ) → ( 1st ‘ ( 𝐺𝑁 ) ) < ( 2nd ‘ ( 𝐺𝑁 ) ) )

Proof

Step Hyp Ref Expression
1 ruc.1 ( 𝜑𝐹 : ℕ ⟶ ℝ )
2 ruc.2 ( 𝜑𝐷 = ( 𝑥 ∈ ( ℝ × ℝ ) , 𝑦 ∈ ℝ ↦ ( ( ( 1st𝑥 ) + ( 2nd𝑥 ) ) / 2 ) / 𝑚 if ( 𝑚 < 𝑦 , ⟨ ( 1st𝑥 ) , 𝑚 ⟩ , ⟨ ( ( 𝑚 + ( 2nd𝑥 ) ) / 2 ) , ( 2nd𝑥 ) ⟩ ) ) )
3 ruc.4 𝐶 = ( { ⟨ 0 , ⟨ 0 , 1 ⟩ ⟩ } ∪ 𝐹 )
4 ruc.5 𝐺 = seq 0 ( 𝐷 , 𝐶 )
5 2fveq3 ( 𝑘 = 0 → ( 1st ‘ ( 𝐺𝑘 ) ) = ( 1st ‘ ( 𝐺 ‘ 0 ) ) )
6 2fveq3 ( 𝑘 = 0 → ( 2nd ‘ ( 𝐺𝑘 ) ) = ( 2nd ‘ ( 𝐺 ‘ 0 ) ) )
7 5 6 breq12d ( 𝑘 = 0 → ( ( 1st ‘ ( 𝐺𝑘 ) ) < ( 2nd ‘ ( 𝐺𝑘 ) ) ↔ ( 1st ‘ ( 𝐺 ‘ 0 ) ) < ( 2nd ‘ ( 𝐺 ‘ 0 ) ) ) )
8 7 imbi2d ( 𝑘 = 0 → ( ( 𝜑 → ( 1st ‘ ( 𝐺𝑘 ) ) < ( 2nd ‘ ( 𝐺𝑘 ) ) ) ↔ ( 𝜑 → ( 1st ‘ ( 𝐺 ‘ 0 ) ) < ( 2nd ‘ ( 𝐺 ‘ 0 ) ) ) ) )
9 2fveq3 ( 𝑘 = 𝑛 → ( 1st ‘ ( 𝐺𝑘 ) ) = ( 1st ‘ ( 𝐺𝑛 ) ) )
10 2fveq3 ( 𝑘 = 𝑛 → ( 2nd ‘ ( 𝐺𝑘 ) ) = ( 2nd ‘ ( 𝐺𝑛 ) ) )
11 9 10 breq12d ( 𝑘 = 𝑛 → ( ( 1st ‘ ( 𝐺𝑘 ) ) < ( 2nd ‘ ( 𝐺𝑘 ) ) ↔ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) )
12 11 imbi2d ( 𝑘 = 𝑛 → ( ( 𝜑 → ( 1st ‘ ( 𝐺𝑘 ) ) < ( 2nd ‘ ( 𝐺𝑘 ) ) ) ↔ ( 𝜑 → ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) )
13 2fveq3 ( 𝑘 = ( 𝑛 + 1 ) → ( 1st ‘ ( 𝐺𝑘 ) ) = ( 1st ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) )
14 2fveq3 ( 𝑘 = ( 𝑛 + 1 ) → ( 2nd ‘ ( 𝐺𝑘 ) ) = ( 2nd ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) )
15 13 14 breq12d ( 𝑘 = ( 𝑛 + 1 ) → ( ( 1st ‘ ( 𝐺𝑘 ) ) < ( 2nd ‘ ( 𝐺𝑘 ) ) ↔ ( 1st ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) < ( 2nd ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) ) )
16 15 imbi2d ( 𝑘 = ( 𝑛 + 1 ) → ( ( 𝜑 → ( 1st ‘ ( 𝐺𝑘 ) ) < ( 2nd ‘ ( 𝐺𝑘 ) ) ) ↔ ( 𝜑 → ( 1st ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) < ( 2nd ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) ) ) )
17 2fveq3 ( 𝑘 = 𝑁 → ( 1st ‘ ( 𝐺𝑘 ) ) = ( 1st ‘ ( 𝐺𝑁 ) ) )
18 2fveq3 ( 𝑘 = 𝑁 → ( 2nd ‘ ( 𝐺𝑘 ) ) = ( 2nd ‘ ( 𝐺𝑁 ) ) )
19 17 18 breq12d ( 𝑘 = 𝑁 → ( ( 1st ‘ ( 𝐺𝑘 ) ) < ( 2nd ‘ ( 𝐺𝑘 ) ) ↔ ( 1st ‘ ( 𝐺𝑁 ) ) < ( 2nd ‘ ( 𝐺𝑁 ) ) ) )
20 19 imbi2d ( 𝑘 = 𝑁 → ( ( 𝜑 → ( 1st ‘ ( 𝐺𝑘 ) ) < ( 2nd ‘ ( 𝐺𝑘 ) ) ) ↔ ( 𝜑 → ( 1st ‘ ( 𝐺𝑁 ) ) < ( 2nd ‘ ( 𝐺𝑁 ) ) ) ) )
21 0lt1 0 < 1
22 21 a1i ( 𝜑 → 0 < 1 )
23 1 2 3 4 ruclem4 ( 𝜑 → ( 𝐺 ‘ 0 ) = ⟨ 0 , 1 ⟩ )
24 23 fveq2d ( 𝜑 → ( 1st ‘ ( 𝐺 ‘ 0 ) ) = ( 1st ‘ ⟨ 0 , 1 ⟩ ) )
25 c0ex 0 ∈ V
26 1ex 1 ∈ V
27 25 26 op1st ( 1st ‘ ⟨ 0 , 1 ⟩ ) = 0
28 24 27 eqtrdi ( 𝜑 → ( 1st ‘ ( 𝐺 ‘ 0 ) ) = 0 )
29 23 fveq2d ( 𝜑 → ( 2nd ‘ ( 𝐺 ‘ 0 ) ) = ( 2nd ‘ ⟨ 0 , 1 ⟩ ) )
30 25 26 op2nd ( 2nd ‘ ⟨ 0 , 1 ⟩ ) = 1
31 29 30 eqtrdi ( 𝜑 → ( 2nd ‘ ( 𝐺 ‘ 0 ) ) = 1 )
32 22 28 31 3brtr4d ( 𝜑 → ( 1st ‘ ( 𝐺 ‘ 0 ) ) < ( 2nd ‘ ( 𝐺 ‘ 0 ) ) )
33 1 adantr ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → 𝐹 : ℕ ⟶ ℝ )
34 2 adantr ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → 𝐷 = ( 𝑥 ∈ ( ℝ × ℝ ) , 𝑦 ∈ ℝ ↦ ( ( ( 1st𝑥 ) + ( 2nd𝑥 ) ) / 2 ) / 𝑚 if ( 𝑚 < 𝑦 , ⟨ ( 1st𝑥 ) , 𝑚 ⟩ , ⟨ ( ( 𝑚 + ( 2nd𝑥 ) ) / 2 ) , ( 2nd𝑥 ) ⟩ ) ) )
35 1 2 3 4 ruclem6 ( 𝜑𝐺 : ℕ0 ⟶ ( ℝ × ℝ ) )
36 35 ffvelrnda ( ( 𝜑𝑛 ∈ ℕ0 ) → ( 𝐺𝑛 ) ∈ ( ℝ × ℝ ) )
37 36 adantrr ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( 𝐺𝑛 ) ∈ ( ℝ × ℝ ) )
38 xp1st ( ( 𝐺𝑛 ) ∈ ( ℝ × ℝ ) → ( 1st ‘ ( 𝐺𝑛 ) ) ∈ ℝ )
39 37 38 syl ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( 1st ‘ ( 𝐺𝑛 ) ) ∈ ℝ )
40 xp2nd ( ( 𝐺𝑛 ) ∈ ( ℝ × ℝ ) → ( 2nd ‘ ( 𝐺𝑛 ) ) ∈ ℝ )
41 37 40 syl ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( 2nd ‘ ( 𝐺𝑛 ) ) ∈ ℝ )
42 nn0p1nn ( 𝑛 ∈ ℕ0 → ( 𝑛 + 1 ) ∈ ℕ )
43 ffvelrn ( ( 𝐹 : ℕ ⟶ ℝ ∧ ( 𝑛 + 1 ) ∈ ℕ ) → ( 𝐹 ‘ ( 𝑛 + 1 ) ) ∈ ℝ )
44 1 42 43 syl2an ( ( 𝜑𝑛 ∈ ℕ0 ) → ( 𝐹 ‘ ( 𝑛 + 1 ) ) ∈ ℝ )
45 44 adantrr ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( 𝐹 ‘ ( 𝑛 + 1 ) ) ∈ ℝ )
46 eqid ( 1st ‘ ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) ) = ( 1st ‘ ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) )
47 eqid ( 2nd ‘ ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) ) = ( 2nd ‘ ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) )
48 simprr ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) )
49 33 34 39 41 45 46 47 48 ruclem2 ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( ( 1st ‘ ( 𝐺𝑛 ) ) ≤ ( 1st ‘ ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) ) ∧ ( 1st ‘ ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) ) < ( 2nd ‘ ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) ) ∧ ( 2nd ‘ ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) ) ≤ ( 2nd ‘ ( 𝐺𝑛 ) ) ) )
50 49 simp2d ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( 1st ‘ ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) ) < ( 2nd ‘ ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) ) )
51 1 2 3 4 ruclem7 ( ( 𝜑𝑛 ∈ ℕ0 ) → ( 𝐺 ‘ ( 𝑛 + 1 ) ) = ( ( 𝐺𝑛 ) 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) )
52 51 adantrr ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( 𝐺 ‘ ( 𝑛 + 1 ) ) = ( ( 𝐺𝑛 ) 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) )
53 1st2nd2 ( ( 𝐺𝑛 ) ∈ ( ℝ × ℝ ) → ( 𝐺𝑛 ) = ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ )
54 37 53 syl ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( 𝐺𝑛 ) = ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ )
55 54 oveq1d ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( ( 𝐺𝑛 ) 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) = ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) )
56 52 55 eqtrd ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( 𝐺 ‘ ( 𝑛 + 1 ) ) = ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) )
57 56 fveq2d ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( 1st ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) = ( 1st ‘ ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) ) )
58 56 fveq2d ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( 2nd ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) = ( 2nd ‘ ( ⟨ ( 1st ‘ ( 𝐺𝑛 ) ) , ( 2nd ‘ ( 𝐺𝑛 ) ) ⟩ 𝐷 ( 𝐹 ‘ ( 𝑛 + 1 ) ) ) ) )
59 50 57 58 3brtr4d ( ( 𝜑 ∧ ( 𝑛 ∈ ℕ0 ∧ ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) ) → ( 1st ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) < ( 2nd ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) )
60 59 expr ( ( 𝜑𝑛 ∈ ℕ0 ) → ( ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) → ( 1st ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) < ( 2nd ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) ) )
61 60 expcom ( 𝑛 ∈ ℕ0 → ( 𝜑 → ( ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) → ( 1st ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) < ( 2nd ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) ) ) )
62 61 a2d ( 𝑛 ∈ ℕ0 → ( ( 𝜑 → ( 1st ‘ ( 𝐺𝑛 ) ) < ( 2nd ‘ ( 𝐺𝑛 ) ) ) → ( 𝜑 → ( 1st ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) < ( 2nd ‘ ( 𝐺 ‘ ( 𝑛 + 1 ) ) ) ) ) )
63 8 12 16 20 32 62 nn0ind ( 𝑁 ∈ ℕ0 → ( 𝜑 → ( 1st ‘ ( 𝐺𝑁 ) ) < ( 2nd ‘ ( 𝐺𝑁 ) ) ) )
64 63 impcom ( ( 𝜑𝑁 ∈ ℕ0 ) → ( 1st ‘ ( 𝐺𝑁 ) ) < ( 2nd ‘ ( 𝐺𝑁 ) ) )