Metamath Proof Explorer


Theorem aks4d1lem1

Description: Technical lemma to reduce proof size. (Contributed by metakunt, 14-Nov-2024)

Ref Expression
Hypotheses aks4d1lem1.1 ⊢ φ → N ∈ ℤ ≥ 3
aks4d1lem1.2 ⊢ B = log 2 N 5
Assertion aks4d1lem1 ⊢ φ → B ∈ ℕ ∧ 9 < B

Proof

Step Hyp Ref Expression
1 aks4d1lem1.1 ⊢ φ → N ∈ ℤ ≥ 3
2 aks4d1lem1.2 ⊢ B = log 2 N 5
3 2re ⊢ 2 ∈ ℝ
4 3 a1i ⊢ φ → 2 ∈ ℝ
5 2pos ⊢ 0 < 2
6 5 a1i ⊢ φ → 0 < 2
7 eluzelz ⊢ N ∈ ℤ ≥ 3 → N ∈ ℤ
8 1 7 syl ⊢ φ → N ∈ ℤ
9 8 zred ⊢ φ → N ∈ ℝ
10 0red ⊢ φ → 0 ∈ ℝ
11 3re ⊢ 3 ∈ ℝ
12 11 a1i ⊢ φ → 3 ∈ ℝ
13 3pos ⊢ 0 < 3
14 13 a1i ⊢ φ → 0 < 3
15 eluzle ⊢ N ∈ ℤ ≥ 3 → 3 ≤ N
16 1 15 syl ⊢ φ → 3 ≤ N
17 10 12 9 14 16 ltletrd ⊢ φ → 0 < N
18 1red ⊢ φ → 1 ∈ ℝ
19 1lt2 ⊢ 1 < 2
20 19 a1i ⊢ φ → 1 < 2
21 18 20 ltned ⊢ φ → 1 ≠ 2
22 21 necomd ⊢ φ → 2 ≠ 1
23 4 6 9 17 22 relogbcld ⊢ φ → log 2 N ∈ ℝ
24 5nn0 ⊢ 5 ∈ ℕ 0
25 24 a1i ⊢ φ → 5 ∈ ℕ 0
26 23 25 reexpcld ⊢ φ → log 2 N 5 ∈ ℝ
27 26 ceilcld ⊢ φ → log 2 N 5 ∈ ℤ
28 9re ⊢ 9 ∈ ℝ
29 28 a1i ⊢ φ → 9 ∈ ℝ
30 27 zred ⊢ φ → log 2 N 5 ∈ ℝ
31 9pos ⊢ 0 < 9
32 31 a1i ⊢ φ → 0 < 9
33 9 16 3lexlogpow5ineq4 ⊢ φ → 9 < log 2 N 5
34 ceilge ⊢ log 2 N 5 ∈ ℝ → log 2 N 5 ≤ log 2 N 5
35 26 34 syl ⊢ φ → log 2 N 5 ≤ log 2 N 5
36 29 26 30 33 35 ltletrd ⊢ φ → 9 < log 2 N 5
37 10 29 30 32 36 lttrd ⊢ φ → 0 < log 2 N 5
38 27 37 jca ⊢ φ → log 2 N 5 ∈ ℤ ∧ 0 < log 2 N 5
39 elnnz ⊢ log 2 N 5 ∈ ℕ ↔ log 2 N 5 ∈ ℤ ∧ 0 < log 2 N 5
40 38 39 sylibr ⊢ φ → log 2 N 5 ∈ ℕ
41 2 eleq1i ⊢ B ∈ ℕ ↔ log 2 N 5 ∈ ℕ
42 40 41 sylibr ⊢ φ → B ∈ ℕ
43 2 a1i ⊢ φ → B = log 2 N 5
44 36 43 breqtrrd ⊢ φ → 9 < B
45 42 44 jca ⊢ φ → B ∈ ℕ ∧ 9 < B