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Metamath Proof Explorer

Theorem chtge0

Description: The Chebyshev function is always positive. (Contributed by Mario Carneiro, 15-Sep-2014)

Ref Expression
Assertion chtge0 ( 𝐴 ∈ ℝ → 0 ≤ ( θ ‘ 𝐴 ) )

Proof

Step Hyp Ref Expression
1 ppifi ⊢ ( 𝐴 ∈ ℝ → ( ( 0 [,] 𝐴 ) ∩ ℙ ) ∈ Fin )
2 simpr ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ) → 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) )
3 2 elin2d ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ) → 𝑝 ∈ ℙ )
4 prmuz2 ⊢ ( 𝑝 ∈ ℙ → 𝑝 ∈ ( ℤ≥ ‘ 2 ) )
5 3 4 syl ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ) → 𝑝 ∈ ( ℤ≥ ‘ 2 ) )
6 eluz2b2 ⊢ ( 𝑝 ∈ ( ℤ≥ ‘ 2 ) ↔ ( 𝑝 ∈ ℕ ∧ 1 < 𝑝 ) )
7 5 6 sylib ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ) → ( 𝑝 ∈ ℕ ∧ 1 < 𝑝 ) )
8 7 simpld ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ) → 𝑝 ∈ ℕ )
9 8 nnrpd ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ) → 𝑝 ∈ ℝ+ )
10 9 relogcld ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ) → ( log ‘ 𝑝 ) ∈ ℝ )
11 8 nnred ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ) → 𝑝 ∈ ℝ )
12 7 simprd ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ) → 1 < 𝑝 )
13 11 12 rplogcld ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ) → ( log ‘ 𝑝 ) ∈ ℝ+ )
14 13 rpge0d ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ) → 0 ≤ ( log ‘ 𝑝 ) )
15 1 10 14 fsumge0 ⊢ ( 𝐴 ∈ ℝ → 0 ≤ Σ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ( log ‘ 𝑝 ) )
16 chtval ⊢ ( 𝐴 ∈ ℝ → ( θ ‘ 𝐴 ) = Σ 𝑝 ∈ ( ( 0 [,] 𝐴 ) ∩ ℙ ) ( log ‘ 𝑝 ) )
17 15 16 breqtrrd ⊢ ( 𝐴 ∈ ℝ → 0 ≤ ( θ ‘ 𝐴 ) )