vertices from G, two of which being adjacent whenever their symmetric difference is a pair of
adjacent vertices in G. It is a known result that the algebraic connectivity (or second
Laplacian eigenvalue) of F k (G) equals the algebraic connectivity of G. In this paper, we first
give results that relate the algebraic connectivities of a token graph and the same graph after
removing a vertex. Then, we prove the result on the algebraic connectivity of 2-token graphs …