A bound for two numbers in the unit interval

Proved

WorkbookSource.problem_47673

by wamlart · Sep 12, 2026 · Mathlib 0df444a (Lean v4.33.1)

lean-workbooksource-checked

If $a,b\in [0,1]$ then $a+(b-ab)\geq a\geq 0$ .

Source: InternLM Lean-Workbook, record lean_workbook_47673 (Apache-2.0). The complete source proposition and its explicit variable declarations are preserved.

Preamble

import Mathlib
open Real

Formal statement

theorem WorkbookSource.problem_47673 (a b: ℝ) (ha : 0 <= a ∧ a <= 1) (hb : 0 <= b ∧ b <= 1): a + (b - a*b) >= a ∧ a >= 0  :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook/blob/main/lean_workbook.json, record lean_workbook_47673; Apache-2.0

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