English
The rational numbers form a field.
Русский
Рациональные числа образуют поле.
LaTeX
$$$\mathbb{Q} \text{ is a field}$$$
Lean4
instance instField : Field ℚ where
__ := commRing
__ := commGroupWithZero
nnqsmul := _
nnqsmul_def := fun _ _ => rfl
qsmul := _
qsmul_def := fun _ _ => rfl
nnratCast_def q := by rw [← NNRat.den_coe, ← Int.cast_natCast q.num, ← NNRat.num_coe]; exact (num_div_den _).symm
ratCast_def _ := (num_div_den _).symm