OKlibrary  0.2.1.6
Hypergraphs.hpp File Reference

Plans regarding graphs and hypergraph constructions from clause-sets. More...

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## Detailed Description

Plans regarding graphs and hypergraph constructions from clause-sets.

Todo:
Organisation
• Should we distinguish between Graphs.mac and Hypergraphs.mac?
Todo:
Lazy combinatorial matrices
• For the different combinatorial matrices of clause-sets, it seems best to provide all three different types of implementations (compare the discussion "Memoisation for general graphs and multigraphs" in ComputerAlgebra/Graphs/Lisp/plans/general.hpp).
• The cm's which always (re)compute their values, as we have them now, provide the definitions.
• Perhaps from them via some general framework we obtain the instantiated matrices (with values stored in arrays), and the hashed matrics.
Todo:
Implication graphs
• DONE Given a (boolean) clause-set F, extract the clauses {a,b} of length 1 or 2, and create the directed graph with vertices the literals, and edges from -a to b and from -b to a.
• Using graph_draw(dg2mdg(implication_dg_fcs(FF))):
1. The basic problem is that the vertex labels often cannot be seen properly.
2. If the graph is rather small,
```draw_graph(G,show_label=true,head_length=0.05,label_alignment=center,vertex_size=5,head_length=0.1);
```
yields reasonable results.

Definition in file Hypergraphs.hpp.