Metamath Proof Explorer


Theorem ubioc1

Description: The upper bound belongs to an open-below, closed-above interval. See ubicc2 . (Contributed by FL, 29-May-2014)

Ref Expression
Assertion ubioc1 ⊢ A ∈ ℝ * ∧ B ∈ ℝ * ∧ A < B → B ∈ A B

Proof

Step Hyp Ref Expression
1 simp2 ⊢ A ∈ ℝ * ∧ B ∈ ℝ * ∧ A < B → B ∈ ℝ *
2 simp3 ⊢ A ∈ ℝ * ∧ B ∈ ℝ * ∧ A < B → A < B
3 xrleid ⊢ B ∈ ℝ * → B ≤ B
4 3 3ad2ant2 ⊢ A ∈ ℝ * ∧ B ∈ ℝ * ∧ A < B → B ≤ B
5 elioc1 ⊢ A ∈ ℝ * ∧ B ∈ ℝ * → B ∈ A B ↔ B ∈ ℝ * ∧ A < B ∧ B ≤ B
6 5 3adant3 ⊢ A ∈ ℝ * ∧ B ∈ ℝ * ∧ A < B → B ∈ A B ↔ B ∈ ℝ * ∧ A < B ∧ B ≤ B
7 1 2 4 6 mpbir3and ⊢ A ∈ ℝ * ∧ B ∈ ℝ * ∧ A < B → B ∈ A B