2 papers
math.NT2026
The ring of Weyl invariant Jacobi forms
Kazuhiro Sakai
We prove that the ring of Weyl invariant weak Jacobi forms is isomorphic to that of joint covariants of a binary sextic and a binary quartic form. The ring is therefore finit…
math.NT2025
The ring of triality invariants
Kazuhiro Sakai
triality invariants are modular forms as well as invariant polynomials for a fiber product of the modular group and the Weyl group of type . We show that the ring of $D_…