Instance bindOptMonotonic
{A B} (g : G (option A)) (f : A -> G (option B))
`{SizeMonotonic _ g} `{forall x, SizeMonotonic (f x)} :
SizeMonotonic (bindGenOpt g f).

Lemma semBindOptSizeMonotonicIncl_r {A B} (g : G (option A)) (f : A -> G (option B)) (s1 : set A) (s2 : A -> set B) :
semGen g \subset (Some @: s1) :|: [set None] ->
(forall x, semGen (f x) \subset Some @: (s2 x) :|: [set None]) ->
semGen (bindGenOpt g f) \subset Some @: (\bigcup_(a in s1) s2 a) :|: [set None].