English
The edistance is symmetric: edist(f,g) = edist(g,f).
Русский
Расстояние в эвклидовом виде симметрично: edist(f,g) = edist(g,f).
LaTeX
$$$$edist(f,g)=edist(g,f)$$$$
Lean4
/-- This holds independent of `p` and does not require `[Fact (1 ≤ p)]`. We keep it separate
from `pi_Lp.pseudo_emetric_space` so it can be used also for `p < 1`. -/
protected theorem edist_comm (f g : PiLp p β) : edist f g = edist g f :=
by
rcases p.trichotomy with (rfl | rfl | h)
· simp only [edist_eq_card, edist_comm]
· simp only [edist_eq_iSup, edist_comm]
· simp only [edist_eq_sum h, edist_comm]