@J.Rafiee Thank you very much sir, i will assume ideality on the multilayers of graphene.

Interesting question. I can not say much about the electromagnetic properties of graphene. However, in elasticity, we have a theorem that tells us that any elastic cell that possesses symmetry w/r to rotation on 60 degrees, should result in isotropy. From that perspective, any multilayered graphene configuration should not be different from a single layer - altogether they should still be symmetric w/r to such a rotation. Of course that does not account any non-additive effects, that can occur when multiple graphene layers are stacked.

Hi Minas,

If we are talking about the elastic properties, ideal single-layer graphene indeed can be considered as an isotropic material due to its symmetry (as Dr. Igor Ostanin already has answered). You can find a prove here Chapter On the Isotropic Elastic Properties of Graphene Crystal Lattice

But in the case of the large strains, obviously, the symmetry is broken, and in this case, graphene is not isotropic anymore.

Moreover, in the case of thermal properties, even the ideal single-layered graphene is anisotropic.

Ideal multilayered graphene then can be considered as a transversely isotropic material (in the case of small strains).