On the exponent set of nonnegative primitive tensors
  In this paper, we present a necessary and sufficient condition for a nonnegative tensor to be a primitive one, show that the exponent set of nonnegative primitive tensors with order $m(\ge n)$ and dimension $n$ is $\{k| 1\le k\le (n-1)^2+1\}. $ 
Zilong He, Pingzhi Yuan, Lihua You
math.CO