English
If f1 → f2 is l-equivalent and g1 → g2 is l-equivalent, then IsBigOWith c l f1 g1 is equivalent to IsBigOWith c l f2 g2.
Русский
Если f1 ≡ f2 по l и g1 ≡ g2 по l, то IsBigOWith c l f1 g1 эквивалентно IsBigOWith c l f2 g2.
LaTeX
$$$ IsBigOWith\ c\ l\ f1\ g1 \leftrightarrow IsBigOWith\ c\ l\ f2\ g2 $$$
Lean4
theorem isBigOWith_congr (hc : c₁ = c₂) (hf : f₁ =ᶠ[l] f₂) (hg : g₁ =ᶠ[l] g₂) :
IsBigOWith c₁ l f₁ g₁ ↔ IsBigOWith c₂ l f₂ g₂ :=
by
simp only [IsBigOWith_def]
subst c₂
apply Filter.eventually_congr
filter_upwards [hf, hg] with _ e₁ e₂
rw [e₁, e₂]