Sharp estimates for Jacobi heat kernels in double conic domains

We study the even and odd Jacobi heat kernels defined in the context of the multidimensional double cone and its surface, the multidimensional hyperboloid and its surface, and the multidimensional paraboloid and its surface. By integrating the framework of Jacobi polynomials on these domains, as analyzed by Xu, with contemporary methods developed by Nowak, Sjögren, and Szarek for obtaining sharp estimates of the spherical heat kernel, we establish genuinely sharp estimates for the even and odd Jacobi heat kernel in the double conic settings, and for the even Jacobi heat kernel on hyperbolic settings. We also discuss the limitations encountered in extending these results to the remaining settings.