User Portlet User Portlet

Discussions
I'm having the following issue that can not find a solution , by using this boundary condition u[0, t] == 1, v[0, t] == u[1, t], w[0, t] == v[1, t], z[0, t] == w[1, t] that Mathematica does not understand, someone please...
Truth is not in the SAME , thanks for watching , but the domain and distinguished and STILL have not a satisfactory answer. I appreciate any help !
I'm having the following issue that can not find a solution , by using this boundary condition v[0, t] == u[1, t] that Mathematica does not understand, someone please help me! NDSolve[{ D[u[x, t], t] == D[u[x, t], x, x] - u[x, t],...