English
Real.toNNReal (r+p) = Real.toNNReal r + Real.toNNReal p for r, p ≥ 0.
Русский
Если r,p ≥ 0, то toNNReal(r+p) = toNNReal(r) + toNNReal(p).
LaTeX
$$$$ \operatorname{toNNReal}(r+p) = \operatorname{toNNReal}(r) + \operatorname{toNNReal}(p) \quad\text{for } r,p \ge 0. $$$$
Lean4
@[simp]
theorem toNNReal_add {r p : ℝ} (hr : 0 ≤ r) (hp : 0 ≤ p) : Real.toNNReal (r + p) = Real.toNNReal r + Real.toNNReal p :=
NNReal.eq <| by simp [hr, hp, add_nonneg]