SearcharxivSearch

arXiv · 2607.06956

Fixed Points, a Predictor-Impossibility Theorem, and Applications

Abstract

We introduce an activation hierarchy consisting of stage machines, stage domains, and stage languages generated by an activation operator. The central result is a Predictor-Impossibility Theorem (PIT), which shows that no effective predictor family can uniformly determine all stage languages of the hierarchy. The proof combines the semantic activation construction with the S-m-n Theorem and Kleene's Recursion Theorem to obtain a self-referential fixed point that yields a contradiction. We then define an aggregate language MIS and establish a slice theorem connecting aggregate inputs to individual stage languages. This provides a bridge from polynomial-time decidability of MIS to the existence of a predictor family. By PIT, the aggregate language is, therefore, not polynomial-time decidable. Under the aggregate growth condition defining valid aggregate objects, MIS is shown to belong to NP. Combining these two results yields MIS in NP-P. The paper is organized so that PIT stands independently as a recursion-theoretic result, while the complexity-theoretic consequences are derived from the aggregate-language framework.

Explore related subjects

Keep this discovery

BibTeXRIS

Tom Altman. 2026-07-08. Fixed Points, a Predictor-Impossibility Theorem, and Applications. https://arxiv.org/abs/2607.06956

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

The Computational Complexity of Holant Problems on 4-regular Graphs from the Stable Subgroup Sequence of $SL(2,\mathbb{C})$

The Holant framework provides a general setting for studying counting problems and includes graph homomorphisms (\#GH) and counting constraint satisfaction problems (\#CSP) as special cases. Over the past twenty years, a series of computational complexity dichotomies have been established for Holant problems, but the classification for complex-valued signatures is still open. The main obstacle is the case in which all signatures have even arity. In this paper, we establish a dichotomy for Holant problems with a complex-valued 4-ary signature, which is a key base case for the full classification of Holant problems. We present a new strategy by introducing Schur's theorem, the classification of finite subgroups of $\mathrm{SL}(2,\mathbb{C})$ and stable subgroup sequences into the proof. These new techniques are of independent interest.

cs.CC

Topology inside NC$^1$

We show that ACC$^0$ is precisely what can be computed with constant-width circuits of polynomial size and polylogarithmic genus. This extends a characterization given by Hansen, showing that planar constant-width circuits also characterize ACC$^0$. Thus polylogarithmic genus provides no additional computational power in this model. We consider other generalizations of planarity, including crossing number and thickness. We show that constant-width circuits of polynomial size and thickness two already suffice to capture all of NC$^1$.

cs.CC