English
For sets s,t ⊆ ℝ, the interior of the complex prod equals the prod of interiors: interior(s ×ℂ t) = interior(s) ×ℂ interior(t).
Русский
Для множеств s,t ⊆ ℝ: interior( s ×ℂ t ) = interior(s) ×ℂ interior(t).
LaTeX
$$$\\operatorname{interior}( s \\times\\mathbb{C} t) = \\operatorname{interior}(s) \\times\\mathbb{C} \\operatorname{interior}(t)$$$
Lean4
theorem interior_reProdIm (s t : Set ℝ) : interior (s ×ℂ t) = interior s ×ℂ interior t := by
rw [reProdIm, reProdIm, interior_inter, interior_preimage_re, interior_preimage_im]