problems wiith the notation

[Canavar]

Hello,

i have found a notation, which i never saw before and i can't give some reasonable definition for it.
Perhaps some of you guys have seen it before and can help me.

let k \in \mathbb{Z}^n and N be a constant, what does <k>^N mean?

I will put more of the context, where this appears:
Let P(x) be a polynomial of order m on \mathbb{R}^n. For almost every \alpha \in A, there are constants C,N s.t. \left| P(k+\alpha)\right| \leq C<k>^N \forall k \in \mathbb{Z}^n.

Can you help me?

Regards

[hunt_mat]

I think that maybe that <k>^{N} denotes the average of the elements of k raised to the power N.

[micromass]

Can you give a reference where this appears?