1. Algebraic conditions for $t$-tough graphs Creator: Liu, Bolian and Chen, Siyuan Format: bez média and svazek Type: model:article and TEXT Subject: $t$-tough graph, Laplacian matrix, adjacent matrix, and eigenvalues Language: English Description: We give some algebraic conditions for $t$-tough graphs in terms of the Laplacian eigenvalues and adjacency eigenvalues of graphs. Rights: http://creativecommons.org/publicdomain/mark/1.0/ and policy:public