nprofile1qy2hwumn8ghj7un9d3shjtnddaehgu3wwp6kyqpqjd874v63430gng67kpw5m597f34dr9vr0yhkp8dkmnma8208raysyd6kk0 (nprofile…6kk0) I eventually plan to relax "convertable" to "is a subtelescope".
The point is though that there is a phase distinction whose open modality "forgets singletons", and first we check subtyping (or convertability) with respect to that, and then we check whether an eta-expanded element of A is an element of B. The eta-expansion "observes" whatever refinements have been put on, in any order, because eta expanding a neutral in a singleton type gives you the unique element of that singleton type.