This is the abstract of the paper "An Existence Family for Husimi Operator" by H. Emamirad and Ph. Rogeon. For the whole paper send the command get evolve-l 99-00028 to: "listserv@rz.uni-karlsruhe.de". Instead you may get the paper at "http://ma1serv.mathematik.uni-karlsruhe.de/evolve-l/index.html" too. Abstract: We prove the well-posedness of the quantum Liouville equation in $L^1(\text{\bf R}^{2n})$, provided that the potential of the Schr\"odinger equation lies in some $ H^s(\text{\bf R}^n)$. By regularizing the Wigner function we obtain the Husimi equation which is ill-posed in any $L^p(\text{\bf R}^{2n})$ spaces. We show that for the Husimi operator the maximal and minimal extensions coincide and we construct a $C$-existence family in the sense of R. deLaubenfels which is a new tool for studing this operator.