Constructing a Neuro-Symbolic Mathematician from First Principles

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📝 Original Info

  • Title: Constructing a Neuro-Symbolic Mathematician from First Principles
  • ArXiv ID: 2601.00125
  • Date: 2025-12-31
  • Authors: Keqin Xie

📝 Abstract

Large Language Models (LLMs) exhibit persistent logical failures in complex reasoning due to the lack of an internal axiomatic framework [1] . We propose Mathesis, a neuro-symbolic architecture that encodes mathematical states as higher-order hypergraphs and uses a Symbolic Reasoning Kernel (SRK)-a differentiable logic engine that maps constraints to a continuous energy landscape. By defining a global energy function E(G), where zero energy implies logical consistency, the SRK yields gradient-based signals to train a Hypergraph Transformer Brain, turning proof search into energy minimization. Multi-step deduction is enabled via Monte Carlo Tree Search and Evolutionary Proof Search, guided by learned value functions and semantic unification.

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Large language models (LLMs) achieve strong performance on linguistic tasks and code generation by modeling the statistical distribution of natural language [2]. However, they exhibit systematic failures in formal mathematical reasoning, often generating steps that violate basic axioms-so-called "hallucinations" [1]. This stems from the probabilistic nature of transformer architectures, which lack mechanisms for logical verification or enforcement of semantic constraints. Although chain-of-thought (CoT) prompting induces intermediate reasoning steps, it does not ensure their logical validity: the underlying process remains high-dimensional sequence prediction, not symbolic derivation [3].

Neuro-symbolic architectures aim to combine neural pattern recognition with symbolic rigor. For example, AlphaGeometry solves Olympiad-level geometry problems by coupling a generative model with a symbolic deduction engine [4]. Yet conventional neuro-symbolic systems typically employ non-differentiable solvers that act as black boxes, yielding only sparse binary feedback (e.g., “proof valid/invalid”). Without gradient signals from the symbolic component, the neural module cannot be trained directly to satisfy logical constraints. Prior efforts toward differentiable logic-such as tensor programs or neural logic machines-struggle to scale beyond small, finite domains due to the unbounded search space of mathematics [5].

We introduce Mathesis, a new architecture that overcomes gradient sparsity through a symbolic reasoning kernel (SRK). The SRK acts as a differentiable “physics engine” for logic: it embeds mathematical hypergraphs into a continuous energy landscape where logical consistency corresponds to a zero-energy state. This yields dense, gradient-based feedback for a Hypergraph Transformer Brain, steering its generative policy toward axiom-compliant derivations. Unlike prior approaches, Mathesis encodes mathematical states as higher-order hypergraphs (Section 4), capturing multi-arity relations and nested logical connectives with high fidelity. The system integrates this neuro-symbolic core with structured search strategies-including Monte Carlo tree search (MCTS) and evolutionary proof search (EPS)-to enable deliberate, “System 2” reasoning (Section 6).

To facilitate rigorous neuro-symbolic reasoning, we formalize the mathematical workspace as a structured, higher-order heterogeneous hypergraph. This representation distinguishes between syntactic construction (terms) and semantic truth (facts), and explicitly handles nested logical structures and variable quantification scopes [6].

We define the state of a proof as a tuple tracking structure, truth status, and variable binding scopes.

A mathematical state is a tuple S = (G, F), where G = (V, E) is a directed higher-order hypergraph.

  1. V is the set of nodes, representing mathematical terms (e.g., variables x, constants 0, compound terms x + y).

  2. E is the set of hyperedges, representing relations, operations, and logical connectives.

• To support nested logic (e.g., (A ∧ B) =⇒ C), we adopt a higherorder definition: a hyperedge e ∈ E is an ordered sequence of elements from V ∪ E. That is, an edge can connect nodes or other edges.This structure is essential for capturing the compositional nature of complex logical formulas, a challenge also addressed in modern knowledge hypergraph reasoning [7].

  1. F ⊆ E is the set of Facts. This is a distinguished subset of hyperedges representing assertions currently held to be true within the global context (e.g., axioms, premises, and derived theorems).

Typing System: We define type mappings ϕ V : V → T V and ϕ E : E → T E to enforce semantic consistency.

• Node Types (T V ): {Variable, Constant, CompoundTerm}.

• Hyperedge Types (T E ): We distinguish three semantic categories:

-Constructors (T Con ): Functional operations that define a term. Inputs are drawn from V , and the output maps to a unique

-Predicates (T P red ): Atomic logical assertions. (e.g., Equals(v a , v b ), Parallel(l 1 , l 2 )).

-Connectives (T Conn ): Higher-order logical operators taking edges as inputs. (e.g., Implies(e premise , e conclusion ), And(e 1 , e 2 )).

Quantification and Scoping: To handle quantification (∀, ∃), we introduce Scope Attributes on hyperedges. A quantified statement is represented by a hyperedge e quant of type ForAll or Exists.

• e quant = (V bound , e body )

• V bound ⊂ V : The set of variables bound by this quantifier.

• e body ∈ E: The logical formula (edge) being quantified.

Example: The statement “∀x, (x = x)” is represented by: 1. Term: Node v x (Type: Variable).

  1. Predicate: Edge e eq = (v x , v x ) (Type: Equals).

  2. Quantification: Edge e root = ({v x }, e eq ) (Type: ForAll).

  3. Fact Status: e root ∈ F. Note that e eq is not in F independently; it is only true within the context of the quantifier.

We frame Automated Theorem Proving (ATP) as a search for a valid derivation path that adds the goal stat

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