at the moment. [^10] There is no reason why such a formulation cannot be made, so we shall assume that we have a spectral function calculated in that formulation as function of temperature/density and kinematics, and call it “TSF" (theoretical spectral function). Unfortunately, having such a TSF is not enough to directly confront the ESF. One also has to know precisely what the conditions with which the measurement of the ESF is made are. The heavy-ion experiment typically involves summing over the dilepton emissions as the system evolves in temperature and density as it expands. Many subtle and complex effects, such as for instance the “memory effects" pointed out in [@C-Greiner], will have to be all taken into account. These are formidable complications, one of the major obstructions to meaningfully confronting HLS/VM with experimental data. It is not clear that the theorists have the full control on all these.

Up to date, no one has succeeded in constructing a spectral function as a function of temperature and density that takes fully into account the three ingredients listed above. Presently available is a partial spectral function obtained by Harada and Sasaki [@HS:spectral] in which only the temperature effects in the ingredients 