Non-perturbative graph languages, halting problem and complexity

Abstract

Abstract We explain the foundations of a new class of formal languages for the construction of large Feynman diagrams which contribute to solutions of all combinatorial Dyson–Schwinger equations in a given strongly coupled gauge field theory. Then we build a new Hopf algebraic structure on non-perturbative production rules which leads us to formulate the halting problem for the corresponding replacing–gluing graph grammars in our formal graph languages on the basis of Manin’s renormalization Hopf algebra. In addition, we apply topology of graphons to associate a complexity parameter to this new class of graph grammars. At the final step, we address some applications of our new formal language platform to Quantum Field Theory. The first application concerns the constructive role of non-perturbative graph languages in dealing with quantum gauge symmetries in the context of the Hopf ideals generated by Slavnov–Taylor or Ward–Takahashi identities. The second application concerns the importance of the complexities of non-perturbative replacing–gluing graph grammars in formulating a new generalization of the circuit complexity on the space of Dyson–Schwinger equations. We provide a geometric interpretation of non-perturbative circuit complexities. The third application concerns the impact of non-perturbative replacing–gluing graph grammars in providing some new tools for the computation of the Kolmogorov complexity of Dyson–Schwinger equations.