Description: The generalized sum of nonnegative extended reals is an extended real. (Contributed by Glauco Siliprandi, 11-Oct-2020)
Ref | Expression | ||
---|---|---|---|
Hypotheses | sge0xrclmpt.xph | ⊢ Ⅎ 𝑥 𝜑 | |
sge0xrclmpt.a | ⊢ ( 𝜑 → 𝐴 ∈ 𝑉 ) | ||
sge0xrclmpt.b | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝐴 ) → 𝐵 ∈ ( 0 [,] +∞ ) ) | ||
Assertion | sge0xrclmpt | ⊢ ( 𝜑 → ( Σ^ ‘ ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) ) ∈ ℝ* ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sge0xrclmpt.xph | ⊢ Ⅎ 𝑥 𝜑 | |
2 | sge0xrclmpt.a | ⊢ ( 𝜑 → 𝐴 ∈ 𝑉 ) | |
3 | sge0xrclmpt.b | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝐴 ) → 𝐵 ∈ ( 0 [,] +∞ ) ) | |
4 | iccssxr | ⊢ ( 0 [,] +∞ ) ⊆ ℝ* | |
5 | 1 2 3 | sge0clmpt | ⊢ ( 𝜑 → ( Σ^ ‘ ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) ) ∈ ( 0 [,] +∞ ) ) |
6 | 4 5 | sseldi | ⊢ ( 𝜑 → ( Σ^ ‘ ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) ) ∈ ℝ* ) |