Figure 1.

Example model for nuclear translocation of the nuclear factor of activated T cells (NFAT) [22]. (a) Graph G, (b) all its spanning trees, and (c) the corresponding Kirchhoff polynomial. (d) The graph obtained by rooting G at $v_{N_n}$, (e) the edge deleted graph $G\setminus v_{N_c}{v}_{N_c^{\ast }}$, and (f) the edge contracted graph $G/v_{N_c}{v}_{N_c^{\ast }}$. Vertex labels mark the states that they represent and W denotes a vertex obtained after edge contraction. Highlighted vertices are, respectively, roots of the corresponding spanning tree and of all spanning trees when rooting a graph.