The effect on the adjacency and signless Laplacian spectral radii of uniform hypergraphs by grafting edges

In this paper, we investigate how the adjacency spectral radius and signless Laplacian spectral radius behave when a connected uniform hypergraph is perturbed by grafting edges. We extend the classical theorem of Li and Feng (1979) [10] about spectral radius from connected graphs to connected uniform hypergraphs by using a constructive method. This result also generalizes the results of Cvetković and Simić (2009) [2], and Su et al. (2018) [22]. As applications, we determine the k-uniform supertrees of order n with the first two smallest adjacency spectral radii (signless Laplacian spectral radii, respectively). Also, we determine the k-uniform supertrees of order n with the first two smallest Laplacian spectral radii, in the case when k is even.