A Noncooperative Mixed Parabolic

Concerning positivity, cooperative elliptic and parabolic systems behave like the corresponding equations: a positive source implies that the solution is positive. Systems with a noncooperative coupling do not yield such type of behaviour. For noncooperative elliptic systems there is a restricted, but uniform, positivity result and for the non-cooperative parabolic system there is no positivity result at all. Here we address positivity preserving properties of an intermediate mixed parabolic-elliptic system. The author gratefully acknowledges support from the EU through the project Reaction-Diiusion Equations under contract ERBCHRXCT930409.