We study interval-valued constraint satisfaction problems (CSPs),
in which the aim is to find an assignment of intervals to a given set of
variables subject to constraints on the relative positions of intervals.
Many well-known problems such as Interval Graph Recognition
and Interval Satisfiability can be considered as examples of ... more >>>

In this article we consider a basic problem in the layout of
VLSI-circuits, the channel-routing problem in the knock-knee mode.
We show that knock-knee channel routing with 3-terminal nets is
NP-complete and thereby settling a problem that was open for more
than a decade. In 1987, Sarrafzadeh showed that knock-knee ... more >>>

We show that every resolution proof of the {\em functional} version
$FPHP^m_n$ of the pigeonhole principle (in which one pigeon may not split
between several holes) must have size $\exp\of{\Omega\of{\frac n{(\log
m)^2}}}$. This implies an $\exp\of{\Omega(n^{1/3})}$ bound when the number
of pigeons $m$ is arbitrary.

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