Explicit Solution Equation for Every Combinatorial Problem via Tensor Networks: MeLoCoToN
Alejandro Mata Ali
TL;DR
The paper introduces MeLoCoToN, a general framework that turns any well-posed combinatorial problem into an explicit tensor-network equation whose solution is obtained by contracting a Tensor Logical Circuit (TLC). It builds problem-specific classical logical circuits (LSTC/LSVC/LSMC), tensorizes them via Circuit Tensorization and IOI indexing, and extracts variable values through half partial trace iterations, optionally enhanced by the Motion Onion methods. The framework encompasses a wide range of problem classes (QUBO, QUDO, CSP, TSP, knapsack, scheduling, etc.) and provides concrete tensor constructions for each, along with strategies to approximate or speed up contraction. While acknowledging exponential costs in many cases, the work argues that a polynomial-time contractible physical system would imply that all NP-hard problems are tractable, highlighting a new mathematical lens for combinatorial analysis and potential cross-pollination with quantum-inspired or heuristic approaches. The paper also outlines avenues for optimization, integration with genetic algorithms, and extensions to higher-order and multivariate problems, making MeLoCoToN a unifying, albeit theoretical, perspective on exact solution equations for combinatorial problems.
Abstract
In this paper we show that every combinatorial problem has an exact explicit equation that returns its solution. We present a method to obtain an equation that solves exactly any combinatorial problem, both inversion, constraint satisfaction and optimization, by obtaining its equivalent tensor network. This formulation only requires a basic knowledge of classical logical operators, at a first year level of any computer science degree. These equations are not necessarily computable in a reasonable time, nor do they allow to surpass the state of the art in computational complexity, but they allow to have a new perspective for the mathematical analysis of these problems. These equations computation can be approximated by different methods such as Matrix Product State compression. We also present the equations for numerous combinatorial problems. This work proves that, if there is a physical system capable of contracting in polynomial time the tensor networks presented, every NP-Hard problem can be solved in polynomial time.
