Invertibility in the Flag Kernels Algebra on the Heisenberg Group

Flag kernels are tempered distributions which generalize these of Calderón–Zygmund type. For any homogeneous group \(\mathbb {G}\) the class of operators which acts on \(L^{2}(\mathbb {G})\) by convolution with a flag kernel is closed under composition. In the case of the Heisenberg group we prove the inverse-closed property for this algebra. It means that if an operator from this algebra is invertible on \(L^{2}(\mathbb {G})\), then its inversion remains in the class.