David Mix Barrington, Chi-Jen Lu, Peter Bro Miltersen, Sven Skyum

We show that searching a width k maze is complete for \Pi_k, i.e., for

the k'th level of the AC^0 hierarchy. Equivalently, st-connectivity

for width k grid graphs is complete for \Pi_k. As an application,

we show that there is a data structure solving dynamic st-connectivity

for constant ...
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Emanuele Viola

Suppose each of $k \le n^{o(1)}$ players holds an $n$-bit number $x_i$ in its hand. The players wish to determine if $\sum_{i \le k} x_i = s$. We give a public-coin protocol with error $1\%$ and communication $O(k \lg k)$. The communication bound is independent of $n$, and for $k ... more >>>

Raghav Kulkarni, Miklos Santha

Let $\mathcal{M}$ be a bridgeless matroid on ground set $\{1,\ldots, n\}$ and $f_{\mathcal{M}}: \{0,1\}^n \to \{0, 1\}$ be the indicator function of its independent sets. A folklore fact is that $f_\mathcal{M}$ is ``evasive," i.e., $D(f_\mathcal{M}) = n$ where $D(f)$ denotes the deterministic decision tree complexity of $f.$ Here we prove ... more >>>