Produce graphs that are suitable and efficient for fixpoint computation, notably:

Forward fixpoint computation of an abstract domain over a WTO (which is not memory-efficient).

This implements a regular expression suitable for forward dataflow analysis (concat has been replaced by append), where the regular expression is represented using a term graph.

Weak topological orderings (WTOs) are a hierarchical decomposition of the a graph where each layer is topologically ordered and strongly connected components are aggregated and ordered recursively. This is a very convenient representation to describe an evaluation order to reach a fixpoint.