English
The covolume of a lattice L with respect to μ is nonzero; in particular, the fundamental domain has positive measure.
Русский
Коволюм решетки L относительно μ не равен нулю; следовательно, фундаментальная область имеет положительную меру.
LaTeX
$$$\\operatorname{covolume}(L,\\mu) \\neq 0$$$
Lean4
theorem covolume_ne_zero : covolume L μ ≠ 0 :=
by
rw [covolume_eq_measure_fundamentalDomain L μ (isAddFundamentalDomain (Free.chooseBasis ℤ L) μ),
measureReal_ne_zero_iff (ne_of_lt _)]
· exact measure_fundamentalDomain_ne_zero _
· exact Bornology.IsBounded.measure_lt_top (fundamentalDomain_isBounded _)