On the Hardness of the Noncommutative Determinant

In this paper we study the computational complexity of computing the noncommutative determinant. We first consider the arithmetic circuit complexity of computing the noncommutative determinant polynomial. Then, more generally, we also examine the complexity of computing the determinant (as a function) over noncommutative domains. Our hardness results are summarized below: ? We show that if the noncommutative determinant polynomial has small noncommutative arithmetic circuits then so does the noncommutative permanent. Consequently, the commutative permanent polynomial has small commutative arithmetic circuits. ? For any field F we show that computing the n ? n permanent over F is polynomial-time reducible to computing the 2n ? 2n (noncommutative) determinant whose entries are O(n2 ) ? O(n2 ) matrices over the field F. ? We also derive as a consequence that computing the n ? n permanent over nonnegative rationals is polynomial-time reducible to computing the noncommutative determinant o...

• Type: Conference
• Year: 2010
• Where: STOC
• Authors: Vikraman Arvind and Srikanth Srinivasan
• Keywords: Algorithms, Noncommutative Arithmetic Circuits, Noncommutative Determinant Polynomial, Noncommutative Polynomials, STOC 2010