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A plane graph $G$ defines a cyclic ordering $O(v) = \langle v_1, v_2, \dotsc, n_{\deg(v)}\rangle$ on the neighborhood $N(v)$ of each vertex $v \in V(G)$. A non-intersecting Eulerian circuit $C$ is an Eulerian circuit such that for every vertex $v \in V(G)$ and every choice of four edges $\{a,v\}, \{b,v\}, \{c,v\}, \{d,v\} \in E(G)$ containing $v$, if the cyclic ordering $O(v)$ restricted to $\{a,b,c,d\}$ is $\langle a,b,c,d \rangle$ and $\{a,c\} \in C$, then $\{b,d\} \not\in C$.

I have found several references that claim or prove that every plane Eulerian graph contains a non-intersecting Eulerian circuit and at least one reference that shows how to find one in polynomial time.

Is there a standard reference (preferably a book on graph theory) that shows how to compute a non-intersecting Eulerian circuit in a plane Eulerian graph in polynomial time?

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  • $\begingroup$ A clarification: deciding if a planar graph has a non-intersecting Eulerian circuit (or path) is NP-complete (Bent and Manber,84). But planar graphs with a non-intersecting Eulerian circuit is a strict subclass of planar graphs with an Eulerian circuit so if you have a polynomial time algorithm for computing a non-intersecting Eulerian circuit in a planar Eulerian graph you have also a polynomial time algorithm for computing a non-intersecting Eulerian circuit in planar graphs (just check and discard in polynomial time graphs without an Eulerian circuit). What am I missing? $\endgroup$ May 15, 2014 at 22:20
  • $\begingroup$ @MarzioDeBiasi Bent and Manber used a poor choice of words. Their "non-intersecting Eulerian circuit" is better described and known as an A-trail. See, for example, Andersen and Fleischner. $\endgroup$ May 15, 2014 at 22:55
  • $\begingroup$ Ok, thank you! Can you give the reference, that shows how to find a non-intersecting Eulerian circuit in polynomial time (that you mentioned in the question). $\endgroup$ May 15, 2014 at 23:10
  • $\begingroup$ @MarzioDeBiasi One of the references is Self-nonintersecting and non intersecting chains, which is an English translation of a Russian paper. Its algorithm works for any Eulerian graph with specified cyclic orderings at each vertex. Plane Eulerian graphs are a special case of these. $\endgroup$ May 15, 2014 at 23:19

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