  Abstract. We provide a characterization of classes of filters $\mathbb{D}$
for which the full subcategory $\operatorname{fix}\operatorname{A}_{\mathbb D}$
of $\mathsf{Conv}$ formed by convergences determined by the adherence of
filters of the class $\mathbb{D}$ is simple in $\mathsf{Conv}$. Along the way,
we also elucidate when two classes of filters result in the same category of
adherence-determined convergences. As an application of the main result, we
show that the category of hypotopologies is not simple, thus answering a
question from [25].
