Metamath Proof Explorer


Theorem aaliou3lem5

Description: Lemma for aaliou3 . (Contributed by Stefan O'Rear, 16-Nov-2014)

Ref Expression
Hypotheses aaliou3lem.c 𝐹 = ( 𝑎 ∈ ℕ ↦ ( 2 ↑ - ( ! ‘ 𝑎 ) ) )
aaliou3lem.d 𝐿 = Σ 𝑏 ∈ ℕ ( 𝐹𝑏 )
aaliou3lem.e 𝐻 = ( 𝑐 ∈ ℕ ↦ Σ 𝑏 ∈ ( 1 ... 𝑐 ) ( 𝐹𝑏 ) )
Assertion aaliou3lem5 ( 𝐴 ∈ ℕ → ( 𝐻𝐴 ) ∈ ℝ )

Proof

Step Hyp Ref Expression
1 aaliou3lem.c 𝐹 = ( 𝑎 ∈ ℕ ↦ ( 2 ↑ - ( ! ‘ 𝑎 ) ) )
2 aaliou3lem.d 𝐿 = Σ 𝑏 ∈ ℕ ( 𝐹𝑏 )
3 aaliou3lem.e 𝐻 = ( 𝑐 ∈ ℕ ↦ Σ 𝑏 ∈ ( 1 ... 𝑐 ) ( 𝐹𝑏 ) )
4 oveq2 ( 𝑐 = 𝐴 → ( 1 ... 𝑐 ) = ( 1 ... 𝐴 ) )
5 4 sumeq1d ( 𝑐 = 𝐴 → Σ 𝑏 ∈ ( 1 ... 𝑐 ) ( 𝐹𝑏 ) = Σ 𝑏 ∈ ( 1 ... 𝐴 ) ( 𝐹𝑏 ) )
6 sumex Σ 𝑏 ∈ ( 1 ... 𝐴 ) ( 𝐹𝑏 ) ∈ V
7 5 3 6 fvmpt ( 𝐴 ∈ ℕ → ( 𝐻𝐴 ) = Σ 𝑏 ∈ ( 1 ... 𝐴 ) ( 𝐹𝑏 ) )
8 fzfid ( 𝐴 ∈ ℕ → ( 1 ... 𝐴 ) ∈ Fin )
9 elfznn ( 𝑏 ∈ ( 1 ... 𝐴 ) → 𝑏 ∈ ℕ )
10 9 adantl ( ( 𝐴 ∈ ℕ ∧ 𝑏 ∈ ( 1 ... 𝐴 ) ) → 𝑏 ∈ ℕ )
11 fveq2 ( 𝑎 = 𝑏 → ( ! ‘ 𝑎 ) = ( ! ‘ 𝑏 ) )
12 11 negeqd ( 𝑎 = 𝑏 → - ( ! ‘ 𝑎 ) = - ( ! ‘ 𝑏 ) )
13 12 oveq2d ( 𝑎 = 𝑏 → ( 2 ↑ - ( ! ‘ 𝑎 ) ) = ( 2 ↑ - ( ! ‘ 𝑏 ) ) )
14 ovex ( 2 ↑ - ( ! ‘ 𝑏 ) ) ∈ V
15 13 1 14 fvmpt ( 𝑏 ∈ ℕ → ( 𝐹𝑏 ) = ( 2 ↑ - ( ! ‘ 𝑏 ) ) )
16 2rp 2 ∈ ℝ+
17 nnnn0 ( 𝑏 ∈ ℕ → 𝑏 ∈ ℕ0 )
18 17 faccld ( 𝑏 ∈ ℕ → ( ! ‘ 𝑏 ) ∈ ℕ )
19 18 nnzd ( 𝑏 ∈ ℕ → ( ! ‘ 𝑏 ) ∈ ℤ )
20 19 znegcld ( 𝑏 ∈ ℕ → - ( ! ‘ 𝑏 ) ∈ ℤ )
21 rpexpcl ( ( 2 ∈ ℝ+ ∧ - ( ! ‘ 𝑏 ) ∈ ℤ ) → ( 2 ↑ - ( ! ‘ 𝑏 ) ) ∈ ℝ+ )
22 16 20 21 sylancr ( 𝑏 ∈ ℕ → ( 2 ↑ - ( ! ‘ 𝑏 ) ) ∈ ℝ+ )
23 22 rpred ( 𝑏 ∈ ℕ → ( 2 ↑ - ( ! ‘ 𝑏 ) ) ∈ ℝ )
24 15 23 eqeltrd ( 𝑏 ∈ ℕ → ( 𝐹𝑏 ) ∈ ℝ )
25 10 24 syl ( ( 𝐴 ∈ ℕ ∧ 𝑏 ∈ ( 1 ... 𝐴 ) ) → ( 𝐹𝑏 ) ∈ ℝ )
26 8 25 fsumrecl ( 𝐴 ∈ ℕ → Σ 𝑏 ∈ ( 1 ... 𝐴 ) ( 𝐹𝑏 ) ∈ ℝ )
27 7 26 eqeltrd ( 𝐴 ∈ ℕ → ( 𝐻𝐴 ) ∈ ℝ )