English
For Exists p, biSup_add' holds: (iSup i, iSup x with p i, f i) + a = iSup i, iSup x with p i, a + f i.
Русский
Для существования p, biSup_add' справедливо: (iSup i, iSup x с p i, f i) + a = iSup i, iSup x с p i, a + f i).
LaTeX
$$$ \exists p(i) \rightarrow \left( \iSup_i \iSup_x^{p(i)} f(i) + a = \iSup_i \iSup_x^{p(i)} (a + f(i)) \right) $$$
Lean4
theorem biSup_add {ι : Type*} {s : Set ι} (hs : s.Nonempty) (f : ι → ℕ∞) : (⨆ i ∈ s, f i) + a = ⨆ i ∈ s, f i + a :=
biSup_add' hs _