English
Scalar multiplication commutes with constructing the direct sum element via mk: mk_M_s (c • x) = c • mk_M_s x.
Русский
Умножение на скаляр commuting с конструированием суммы: mk_M_s (c • x) = c • mk_M_s x.
LaTeX
$$$\\mathrm{mk}\\; M\\; s\\; (c \\cdot x) = c \\cdot \\mathrm{mk}\\; M\\; s\\; x$$$
Lean4
/-- Scalar multiplication commutes with direct sums. -/
theorem mk_smul (s : Finset ι) (c : R) (x) : mk M s (c • x) = c • mk M s x :=
(lmk R ι M s).map_smul c x