Vikraman Arvind

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We show that Graph Isomorphism is in the complexity class SPP, and hence it is in ⊕P (in fact, it is in ModkP for each k ≥ 2). We derive this result as a corollary of a more general result: we show that a generic problem FIND-GROUP has an FPSPP algorithm. This general result has other consequences: for example, it follows that the hidden subgroup problem(More)
In this paper we extend a key result of Nisan and Wigderson NW94] to the nondeterministic setting: for all > 0 we show that if there is a language in E = DTIME(2 O(n)) that is hard to approximate by nondeterministic circuits of size 2 n , then there is a pseudorandom generator that can be used to derandomize BP NP (in symbols, BP NP = NP). By applying this(More)
We describe a fixed parameter tractable (fpt) algorithm for Colored Hypergraph Isomorphism, denoted CHI, which has running time (2 b N) O(1), where the parameter b is the maximum size of the color classes of the given hypergraphs and N is the input size. We also describe an fpt algorithm for a parameterized coset intersection problem that is used as a(More)
Motivated by the Hadamard product of matrices we define the Hadamard product of multivariate polynomials and study its arithmetic circuit and branching program complexity. We also give applications and connections to polynomial identity testing. Our main results are the following. • We show that noncommutative polynomial identity testing for algebraic(More)
An undirected graph G is said to be d-distinguishable if there is a d-coloring of its vertex set V (G) such that no nontrivial automorphism of G preserves the coloring. The distinguishing number of a graph G is the minimum d for which it is d-distinguishable. In this paper we design efficient algorithms for computing the distinguishing numbers of trees and(More)
In this paper we study the consequences of the existence of sparse hard sets for NP and other complexity classes under certain types of deterministic randomized and nondeterministic reductions We show that if an NP complete set is bounded truth table reducible to some set that conjunctively reduces to a sparse set then P NP This result subsumes and extends(More)