一句话:构造布尔约束Q_n:存在度2且单项式数多项式的SOS/PCR/ℚ反驳,但任何反驳均需指数级比特复杂度。
本文研究在有理数上的多项式演算消解(PCR/ℚ)与平方和(SOS)证明系统中,反驳的单项式规模与比特复杂度之间的关系。作者构造了一族定义在布尔变量上的多项式约束 Q_n,并证明该约束集同时具有度数为 2 的 SOS 反驳和 PCR/ℚ 反驳,因此其单项式数量仅为多项式级。然而,当有理系数以二进制表示的既约分数形式编码时,任何 SOS 或 PCR/ℚ 反驳都必然具有指数级比特复杂度。该结果说明,单项式数量少并不保证系数表示也小,从而在证明复杂度中严格区分了单项式规模与比特复杂度这两个度量。
In this paper we consider the relationship between monomial-size and bit-complexity in Sums-of-Squares (SOS) in Polynomial Calculus Resolution over rationals (PCR/ℚ). We show that there is a set of polynomial constraints Qnover Boolean variables that has both SOS and PCR/ℚ refutations of degree 2 and thus with only polynomially many monomials, but for which any SOS or PCR/ℚ refutation must have exponential bit-complexity, when the rational coefficients are represented with their reduced fractions written in binary.