# The Complexity of the Ideal Membership Problem for Constrained Problems Over the Boolean Domain

## TL;DR

This paper characterizes the computational complexity of the Ideal Membership Problem for Boolean combinatorial ideals, extending Schaefer's dichotomy and linking it to the tractability of SDP relaxations and Sum-of-Squares proofs.

## Contribution

It extends Schaefer's dichotomy theorem to the Ideal Membership Problem, establishing the boundary between tractable and intractable cases for Boolean constrained problems.

## Key findings

- Identifies the boundary of tractability for the Ideal Membership Problem.
- Provides necessary and sufficient conditions for efficient Theta Body SDP relaxations.
- Links tractability of the Ideal Membership Problem to bounded coefficients in Sum-of-Squares proofs.

## Abstract

Given an ideal $I$ and a polynomial $f$ the Ideal Membership Problem is to test if $f\in I$. This problem is a fundamental algorithmic problem with important applications and notoriously intractable. We study the complexity of the Ideal Membership Problem for combinatorial ideals that arise from constrained problems over the Boolean domain. As our main result, we identify the borderline of tractability. By using Gr\"{o}bner bases techniques, we extend Schaefer's dichotomy theorem [STOC, 1978] which classifies all Constraint Satisfaction Problems over the Boolean domain to be either in P or NP-hard. Moreover, our result implies necessary and sufficient conditions for the efficient computation of Theta Body SDP relaxations, identifying therefore the borderline of tractability for constraint language problems. This paper is motivated by the pursuit of understanding the recently raised issue of bit complexity of Sum-of-Squares proofs [O'Donnell, ITCS, 2017]. Raghavendra and Weitz [ICALP, 2017] show how the Ideal Membership Problem tractability for combinatorial ideals implies bounded coefficients in Sum-of-Squares proofs.