English
For nonunital semirings A and B, IsQuasiregular on the pair (a,b) is equivalent to IsQuasiregular a and IsQuasiregular b.
Русский
Для произведения IsQuasiregular (a,b) эквивалентно IsQuasiregular a и IsQuasiregular b.
LaTeX
$$$IsQuasiregular(\langle a,b \rangle) \;\iff\; IsQuasiregular(a) \land IsQuasiregular(b)$$$
Lean4
theorem isQuasiregular_pi_iff [∀ i, NonUnitalSemiring (κ i)] (x : ∀ i, κ i) :
IsQuasiregular x ↔ ∀ i, IsQuasiregular (x i) :=
by
simp only [isQuasiregular_iff', ← isUnit_map_iff (PreQuasiregular.toPi κ), Pi.isUnit_iff]
congr!