Weizmann Logo
ECCC
Electronic Colloquium on Computational Complexity

Under the auspices of the Computational Complexity Foundation (CCF)

Login | Register | Classic Style



LATEST > REPORTS:
RSS-Feedprevious PreviousNext next

TR10-104 | 29th June 2010
Paul Beame, Widad Machmouchi

Making RAMs Oblivious Requires Superlogarithmic Overhead

Revisions: 3 , Comments: 1

We prove a time-space tradeoff lower bound of $T =
\Omega\left(n\log(\frac{n}{S}) \log \log(\frac{n}{S})\right) $ for
randomized oblivious branching programs to compute $1GAP$, also
known as the pointer jumping problem, a problem for which there is a
simple deterministic time $n$ and space $O(\log n)$ RAM (random
access machine) algorithm.

In ... more >>>


TR10-103 | 28th June 2010
Andreas Krebs, Nutan Limaye, Meena Mahajan

Counting paths in VPA is complete for \#NC$^1$

We give a \#NC$^1$ upper bound for the problem of counting accepting paths in any fixed visibly pushdown automaton. Our algorithm involves a non-trivial adaptation of the arithmetic formula evaluation algorithm of Buss, Cook, Gupta, Ramachandran (BCGR: SICOMP 21(4), 1992). We also show that the problem is \#NC$^1$ hard. Our ... more >>>


TR10-102 | 12th May 2010
Per Kristian Lehre, Carsten Witt

Black-Box Search by Unbiased Variation

Revisions: 1

The complexity theory for black-box algorithms, introduced by
Droste et al. (2006), describes common limits on the efficiency of
a broad class of randomised search heuristics. There is an
obvious trade-off between the generality of the black-box model
and the strength of the bounds that can be proven in such ... more >>>



previous PreviousNext next


ISSN 1433-8092 | Imprint