Database
REAL AND COMPLEX NUMBERS
Order sets
Infinity and the extended real number system (cont.)
xrltled
Metamath Proof Explorer
Description: 'Less than' implies 'less than or equal to' for extended reals.
Deduction form of xrltle . (Contributed by Glauco Siliprandi , 11-Dec-2019)
Ref
Expression
Hypotheses
xrltled.a
⊢ φ → A ∈ ℝ *
xrltled.b
⊢ φ → B ∈ ℝ *
xrltled.altb
⊢ φ → A < B
Assertion
xrltled
⊢ φ → A ≤ B
Proof
Step
Hyp
Ref
Expression
1
xrltled.a
⊢ φ → A ∈ ℝ *
2
xrltled.b
⊢ φ → B ∈ ℝ *
3
xrltled.altb
⊢ φ → A < B
4
xrltle
⊢ A ∈ ℝ * ∧ B ∈ ℝ * → A < B → A ≤ B
5
1 2 4
syl2anc
⊢ φ → A < B → A ≤ B
6
3 5
mpd
⊢ φ → A ≤ B