Total space in Resolution is at least width squared
In this talk we cover some results on the space complexity of Resolution and in particular the new recent connection between total space and width in the title. Given a k-CNF formula F, the width is the minimal integer W such that there exists a Resolution refutation of F with clauses of at most W literals. The total space is the minimal size T of a memory used to write down a Resolution refutation of F, where the size of the memory is measured as the total number of literals it can contain. We show that T=Ω((W−k)2). This connection between total space and width relies on some basic properties of another, perhaps less known, complexity measure in Resolution: the asymmetric width.
The talk is based on a paper appeared in ICALP’16.