English
In characteristic zero, restricting scalars to rationals yields a crystallographic root system; this is the Rat-restriction variant of RestrictScalars.
Русский
В характеристике ноль ограничение скаляров до рациональных чисел даёт кристаллографическую корневую систему; это вариант RestrictScalars на rationals.
LaTeX
$$$\\text{restrictScalarsRat} = \\text{RestrictScalars}_{\\mathbb{Q}}(P)$$$
Lean4
/-- Restriction of scalars to `ℚ` for a crystallographic root pairing in characteristic zero. -/
abbrev restrictScalarsRat [CharZero L] [P.IsCrystallographic] :=
let _i : Module ℚ M := Module.compHom M (algebraMap ℚ L)
let _i : Module ℚ N := Module.compHom N (algebraMap ℚ L)
P.restrictScalars ℚ