Dicyclic Groups and Frobenius Manifolds

The orbits space of an irreducible representation of a finite group is a variety whose coordinate ring is finitely generated by homogeneous invariant polynomials. Boris Dubrovin showed that the orbits spaces of the reflection groups acquire the structure of polynomial Frobenius manifolds. Dubrovin’s method to construct examples of Frobenius manifolds on orbits spaces was carried for other linear representations of discrete groups which have in common that the coordinate rings of the orbits spaces are polynomial rings. In this article, we show that the orbits space of an irreducible representation of a dicyclic group acquires two structures of Frobenius manifolds. The coordinate ring of this orbits space is not a polynomial ring.