Figure 5

One compression step of the MDS method. Small circles represent reactions and big circles represent supernodes that result from earlier steps of compression. A solid arrow represents an edge between two non-compressed nodes in the current compression level. A dashed arrow denotes an edge between a supernode and another node in the network. While calculating the degrees of the non-compressed nodes, only the solid arrows are taken into account. (a) The state of network P during compression level x before the i th intermediate step (i.e., $P_{i-1}^x$). The node with the minimum degree is denoted with v _a and its first neighbor is denoted with v _b . (b) The state of this network after the i th compression step (i.e., $P_i^x$). We denote the node resulted from the compression at this step with v _ab .