P-complete

Ordered Low Degree Vertex Removal (OLDVR)

Category: Graph Theory

Input

An undirected graph $G = (V, E)$ with a numbering on the vertices in $V$, and two designated vertices $u$ and $v$.

Problem

Is there an elimination order on $V$, $v_1, v_2, \ldots, v_n$, satisfying the properties that $u$ is eliminated before $v$ and for $1 \leq i \leq n$, $v_i$ is the lowest numbered vertex of minimum degree in the $(i-1)$-st remaining subgraph of $G$?

Definitions

See OHDVR.

Status

$\P$-complete (Vishwanathan and Sridhar [1], Greenlaw [2]).

Remarks

This is the complementary of OHDVR,

The problem defined in [1] is more restricted than the one presented here. Their graphs are also required to have the property that $u$ appears before $v$ in some minimum elimination sequence if and only if $u$ appears before $v$ in all minimum degree elimination sequences.

References

  1. S. Vishwanathan and M. A. Sridhar (1988). Some results on graph coloring in parallel.
  2. R. Greenlaw (1989). Ordered vertex removal and subgraph problems.
  3. Greenlaw, R., Hoover, H. J., and Ruzzo, W. L. (1995). Limits to Parallel Computation: P-Completeness Theory. Oxford University Press. Problem A.2.11.