I would call it a nonhomogeneous initial condition, but initial conditions have nothing to do with your assumption. Only with nonhomogeneous boundary conditions, this assumption can be applied (or if the PDE is nonhomogeneous). In PDEs, the boundary conditions are conditions in which the substitution is done in the spatial variable such as [imath]x, y, \text{or} \ z[/imath]. On the other hand, a substitution done in the time variable, [imath]t[/imath], is called an initial condition.Would you call the above bdy. condition "homogeneous" or "non-homogeneous" ?