Fig. 7
From: Automated design of dynamic programming schemes for RNA folding with pseudoknots
Representation of the local rewriting of a tree decomposition next to a separator S separating to base pairs \((u_i,v_i)\) and \((u_j,v_j)\), in order to extend a helix by one unit, through the introduction of new vertices x and y. This is used in Theorem 2, in what corresponds in Sect "Interpreting the tree decomposition of a fatgraph expansion as a DP algorithm" to the “diagonal” case