English
For 0 < p.toReal, the distance satisfies dist f g = (∑ dist(f_i,g_i)^{p.toReal})^{1/p.toReal}.
Русский
Для 0 < p.toReal расстояние удовлетворяет dist f g = (∑ dist(f_i,g_i)^{p.toReal})^{1/p.toReal}.
LaTeX
$$$$dist(f,g)=\\left(\\sum_i dist(f_i,g_i)^{p^{\\mathrm{toReal}}}\\right)^{1/p^{\\mathrm{toReal}}}$$$$
Lean4
theorem dist_eq_sum {p : ℝ≥0∞} (hp : 0 < p.toReal) (f g : PiLp p α) :
dist f g = (∑ i, dist (f i) (g i) ^ p.toReal) ^ (1 / p.toReal) :=
let hp' := ENNReal.toReal_pos_iff.mp hp
(if_neg hp'.1.ne').trans (if_neg hp'.2.ne)