Dungey, Nicholas2015-12-132015-12-130379-4024http://hdl.handle.net/1885/93329Let G be a connected Lie group of polynomial growth. We consider m-th order subelliptic differential operators H on G, the semigroups St = e-tH and the corresponding heat kernels Kt. For a large class of H with m ≥ 4 we demonstrate equivalence between tKeywords: Heat kernel; Higher-order differential operators; Lie group20012015-12-12