# P-Completeness of Testing Solutions of Parametric Interval Linear Systems

Chapter
Part of the Studies in Systems, Decision and Control book series (SSDC, volume 276)

## Abstract

We deal with a system of parametric interval linear equations and also with its particular sub-classes defined by symmetry of the constraint matrix. We show that the problem of checking whether a given vector is a solution is a P-complete problem, meaning that there unlikely exists a polynomial closed form arithmetic formula describing the solution set. This is true not only for the general parametric system, but also for the symmetric case with general linear dependencies in the right-hand side. However, we leave as an open problem whether P-completeness concerns also the simplest version of the symmetric solution set with no dependencies in the right-hand side interval vector.

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