English
The support of f.rangeIcc g is contained in the union of supports of f and g.
Русский
Поддержка f.rangeIcc g ⊆ подмножество объединения поддержек f и g.
LaTeX
$$rangeIcc_support_subset : (f.rangeIcc g).support ⊆ f.support ∪ g.support$$
Lean4
theorem support_rangeIcc_subset [DecidableEq ι] [∀ i, DecidableEq (α i)] :
(f.rangeIcc g).support ⊆ f.support ∪ g.support :=
by
refine fun x hx => ?_
by_contra h
refine notMem_support_iff.2 ?_ hx
rw [rangeIcc_apply, notMem_support_iff.1 (notMem_mono subset_union_left h),
notMem_support_iff.1 (notMem_mono subset_union_right h)]
exact Icc_self _