We provide a compendium of problems that are complete for
symmetric logarithmic space (SL). Complete problems are one method
of studying this class for which programming is nonintuitive. A
number of the problems in the list were not previously known to be
complete. A ... more >>>

We propose definitions of $\QAC^0$, the quantum analog of the
classical class $\AC^0$ of constant-depth circuits with AND and OR
gates of arbitrary fan-in, and $\QACC^0[q]$, the analog of the class
$\ACC^0[q]$ where $\Mod_q$ gates are also allowed. We show that it is
possible to make a `cat' state on ... more >>>

This paper deals with the reversible circuits with n input and
output nodes, consisting of the reversible gates FAN-IN=FAN-OUT<3.
We define a normal form of such type of circuits and describe a reduction
algorithm to transform a circuit in this form. Furthermore we use it for
checking whether two circuits ... more >>>

We show that every language accepted by a nondeterministic auxiliary pushdown automaton in polynomial time (that is, every language in SAC$^1$ = LogCFL) can be accepted by a symmetric auxiliary pushdown automaton in polynomial time.

more >>>

Several cellular automata (CA) are known to be universal in the sense that one can simulate arbitrary computations (e.g., circuits or Turing machines) by carefully encoding the computational device and its input into the cells of the CA. In this paper, we consider a different kind of universality proposed by ... more >>>

We give a quantum logspace algorithm for powering contraction matrices, that is, matrices with spectral norm at most 1. The algorithm gets as an input an arbitrary $n\times n$ contraction matrix $A$, and a parameter $T \leq poly(n)$ and outputs the entries of $A^T$, up to (arbitrary) polynomially small additive ... more >>>