Homogeneous Formulas and Symmetric Polynomials
Homogeneous Formulas and Symmetric Polynomials
复制标题
齐次公式和对称多项式
DOI:
10.1007/s00037-011-0007-3
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发表时间:
2009
影响因子:
1.4
通讯作者:
A. Yehudayoff
中科院分区:
文献类型:
--
作者:
P. Hrubes;A. Yehudayoff
We investigate the arithmetic formula complexity of the elementary symmetric polynomials $${S^k_n}$$ . We show that every multilinear homogeneous formula computing $${S^k_n}$$ has size at least $${k^{\Omega(\log k)}n}$$ , and that product-depth d multilinear homogeneous formulas for $${S^k_n}$$ have size at least $${2^{\Omega(k^{1/d})}n}$$ . Since $${S^{n}_{2n}}$$ has a multilinear formula of size O(n2), we obtain a superpolynomial separation between multilinear and multilinear homogeneous formulas. We also show that $${S^k_n}$$ can be computed by homogeneous formulas of size $${k^{O(\log k)}n}$$ , answering a question of Nisan and Wigderson. Finally, we present a superpolynomial separation between monotone and non-monotone formulas in the noncommutative setting, answering a question of Nisan.