modify the focus type of a Setter_ using a Semiring additive
modify the focus type of a Setter_ using a Semigroup combine
modify the focus type of a Setter_ using a Heyting and
modify the focus type of a Setter_ using a Heyting or
modify the focus type of a Setter_ using a Field div
modify the focus type of a Setter_ using a Semiring multiplicative
modify the focus type of a Setter_ using a Ring minus