Remarks on Diffeological Frobenius Reciprocity

A recent paper [R22] established “Frobenius reciprocity” as a bijection $t$ between certain symplectically reduced spaces (which need not be manifolds), and conjectured: 1°) $t$ is a diffeomorphism when these spaces are endowed with their natural subquotient diffeologies, 2°) $t$ respects the reduced diffeological $2$-forms they may (or might not) carry. In this paper, we prove both this conjecture and a similar one on prequantum reduction, and also give new sufficient conditions for the reduced forms to exist. We stop short of proving that they always exist.