Hi - I'm trying to solve a PDE using pdsolve() for the Graetz problem (heat transfer in a pipe). I can solve the PDE and get a general solution, but when I try to solve the equation with the boundary conditions, Maple thinks that the boundary conditions are new functions with the same name. Here is how I am doing it now: > heat := (1-z^2)*(diff(T(y, z), y)) = (diff(z*(diff(T(y, z), z)), z))/z; > cond := T(0, z) = 0, T(y, 1) = 1, diff(T(y, 0), z) = 0; > PDE := [heat, cond]; > sol := pdsolve(PDE, T(y, z)); This throws the error: