de broglie wavelength is postulate?

[einstein_vishnu]

we have seen that for massless (rest) patricle.we can relate the particle nature with the wave nature by einstein's relation.
what about the matter waves?
we cann't use the same relativistic eqation for the momentum energy relation to generalise that to matter waves too,because rest mass is not zero.Griener mentions that it is postulate,if we try other form then we can get rid off complex schrodinger wave function.
waiting for reply

[Galileo]

The Planck-Einstein relations

E=h\nu=\hbar \omega

\vec p=\hbar \vec k
initially held for photons alone.
It was later postulated to hold for material particles as well.

I hope that's an anwer to your question.

[einstein_vishnu]

why should we take the same equations for particle with nonzero rest mass.that derivation includes the relativistic relation between energy, momentum and rest mass.this gives the answer for my valid question of altering debroglie wavelength.
thanks for the reply.