21 research outputs found
On Multistage Learning a Hidden Hypergraph
Learning a hidden hypergraph is a natural generalization of the classical
group testing problem that consists in detecting unknown hypergraph
by carrying out edge-detecting tests. In the given paper we
focus our attention only on a specific family of localized
hypergraphs for which the total number of vertices , the number of
edges , , and the cardinality of any edge ,
. Our goal is to identify all edges of by
using the minimal number of tests. We develop an adaptive algorithm that
matches the information theory bound, i.e., the total number of tests of the
algorithm in the worst case is at most . We also discuss
a probabilistic generalization of the problem.Comment: 5 pages, IEEE conferenc
Concomitant Group Testing
In this paper, we introduce a variation of the group testing problem
capturing the idea that a positive test requires a combination of multiple
``types'' of item. Specifically, we assume that there are multiple disjoint
\emph{semi-defective sets}, and a test is positive if and only if it contains
at least one item from each of these sets. The goal is to reliably identify all
of the semi-defective sets using as few tests as possible, and we refer to this
problem as \textit{Concomitant Group Testing} (ConcGT). We derive a variety of
algorithms for this task, focusing primarily on the case that there are two
semi-defective sets. Our algorithms are distinguished by (i) whether they are
deterministic (zero-error) or randomized (small-error), and (ii) whether they
are non-adaptive, fully adaptive, or have limited adaptivity (e.g., 2 or 3
stages). Both our deterministic adaptive algorithm and our randomized
algorithms (non-adaptive or limited adaptivity) are order-optimal in broad
scaling regimes of interest, and improve significantly over baseline results
that are based on solving a more general problem as an intermediate step (e.g.,
hypergraph learning).Comment: 15 pages, 3 figures, 1 tabl
Optimal Query Complexity for Reconstructing Hypergraphs
In this paper we consider the problem of reconstructing a hidden weighted
hypergraph of constant rank using additive queries. We prove the following: Let
be a weighted hidden hypergraph of constant rank with n vertices and
hyperedges. For any there exists a non-adaptive algorithm that finds the
edges of the graph and their weights using
additive queries. This solves the open problem in [S. Choi, J. H. Kim. Optimal
Query Complexity Bounds for Finding Graphs. {\em STOC}, 749--758,~2008].
When the weights of the hypergraph are integers that are less than
where is the rank of the hypergraph (and therefore for
unweighted hypergraphs) there exists a non-adaptive algorithm that finds the
edges of the graph and their weights using additive queries.
Using the information theoretic bound the above query complexities are tight
Learning Boolean Halfspaces with Small Weights from Membership Queries
We consider the problem of proper learning a Boolean Halfspace with integer
weights from membership queries only. The best known
algorithm for this problem is an adaptive algorithm that asks
membership queries where the best lower bound for the number of membership
queries is [Learning Threshold Functions with Small Weights Using
Membership Queries. COLT 1999]
In this paper we close this gap and give an adaptive proper learning
algorithm with two rounds that asks membership queries. We also give
a non-adaptive proper learning algorithm that asks membership
queries