Dividing up the unrestricted partitions ★★

Author(s): David S.; Newman

Begin with the generating function for unrestricted partitions:

(1+x+x^2+...)(1+x^2+x^4+...)(1+x^3+x^6+...)...

Now change some of the plus signs to minus signs. The resulting series will have coefficients congruent, mod 2, to the coefficients of the generating series for unrestricted partitions. I conjecture that the signs may be chosen such that all the coefficients of the series are either 1, -1, or zero.

Keywords: congruence properties; partition

Perfect cuboid ★★

Author(s):

Conjecture   Does a perfect cuboid exist?

Keywords:

Finding k-edge-outerplanar graph embeddings ★★

Author(s): Bentz

Conjecture   It has been shown that a $ k $-outerplanar embedding for which $ k $ is minimal can be found in polynomial time. Does a similar result hold for $ k $-edge-outerplanar graphs?

Keywords: planar graph; polynomial algorithm

Approximation ratio for k-outerplanar graphs ★★

Author(s): Bentz

Conjecture   Is the approximation ratio for the Maximum Edge Disjoint Paths (MaxEDP) or the Maximum Integer Multiflow problem (MaxIMF) bounded by a constant in $ k $-outerplanar graphs or tree-width graphs?

Keywords: approximation algorithms; planar graph; polynomial algorithm