Answering complex first-order logic (FOL) queries on knowledge graphs is essential for reasoning. Symbolic methods offer interpretability but struggle with incomplete graphs, while neural approaches generalize better but lack transparency. Neural-symbolic models aim to integrate both strengths but often fail to capture the hierarchical structure of logical queries, limiting their effectiveness. We propose HYQNET, a neural-symbolic model for logic query reasoning that fully leverages hyperbolic space. HYQNET decomposes FOL queries into relation projections and logical operations over fuzzy sets, enhancing interpretability. To address missing links, it employs a hyperbolic GNN-based approach for knowledge graph completion in hyperbolic space, effectively embedding the recursive query tree while preserving structural dependencies. By utilizing hyperbolic representations, HYQNET captures the hierarchical nature of logical projection reasoning more effectively than Euclidean-based approaches. Experiments on three benchmark datasets demonstrate that HYQNET achieves strong performance, highlighting the advantages of reasoning in hyperbolic space.
Figures & tables
Figure 1: An example of logical query.
Figure 2: Overview of HyQNet .
Model
avgp
avgn
1p
2p
3p
2i
3i
pi
ip
2u
up
2in
3in
inp
pin
pni
FB15k
GQE
28.0
-
54.6
15.3
10.8
39.7
51.4
27.6
19.1
22.1
11.6
-
-
-
-
-
Q2B
38.0
-
68.0
21.0
14.2
55.1
66.5
39.4
26.1
35.1
16.7
-
-
-
-
-
BetaE
41.6
11.8
65.1
25.7
24.7
55.8
66.5
43.9
28.1
40.1
25.2
14.3
14.7
11.5
6.5
12.4
CQD-CO
46.9
-
89.2
25.3
13.4
74.4
78.3
44.1
33.2
41.8
21.9
-
-
-
-
-
CQD-Beam
58.2
-
89.2
54.3
28.6
74.4
78.3
58.2
67.7
42.4
30.9
-
-
-
-
-
Table 1: Test MRR results (%) on answering FOL queries.
Model
avgp
avgn
1p
2p
3p
2i
3i
pi
ip
2u
up
2in
3in
inp
pin
pni
FB15k
GQE
16.6
-
34.2
8.3
5.0
23.8
34.9
15.5
11.2
11.5
5.6
-
-
-
-
-
Q2B
26.8
-
52.0
12.7
7.8
40.5
53.4
26.7
16.7
22.0
9.4
-
-
-
-
-
BetaE
31.3
5.2
52.0
17.0
16.9
43.5
55.3
32.3
19.3
28.1
16.9
6.4
6.7
5.5
2.0
5.3
CQD-CO
39.7
-
85.8
17.8
9.0
67.6
71.7
34.5
24.5
30.9
15.5
-
-
-
-
-
CQD-Beam
51.9
-
85.8
48.6
22.5
67.6
71.7
51.7
62.3
31.7
25.0
-
-
-
-
-
Table 2: Test H@1 results (%) on answering FOL queries.
Model
avg
1p
2p
3p
2i
3i
pi
ip
2in
3in
inp
pin
pni
Q2B
-
0.301
0.219
0.262
0.331
0.270
0.297
0.139
-
-
-
-
-
BetaE
0.494
0.373
0.478
0.472
0.572
0.397
0.519
0.421
0.622
0.548
0.459
0.465
0.608
GNN-QE
0.952
0.971
0.967
0.926
0.987
0.936
0.937
0.923
0.992
0.985
0.880
0.940
0.991
HyQNet
0.958
0.971
0.970
0.941
0.988
0.938
0.939
0.934
0.990
0.984
0.908
0.948
0.991
Table 3: Spearman’s rank correlation between the model prediction and the number of ground truth answers on FB15k. avg is the average correlation on all 12 query types in the table.
Large Language Models (LLMs) have demonstrated remarkable proficiency in natural language understanding, yet they struggle with strict multi-step reasoning, frequently suffering from hallucinations and inconsistency. Existing solutions like Chain-of-Thought (CoT) lack rigorous verification mechanisms, while standard Retrieval-Augmented Generation (RAG) often misses the complex, structural dependencies inherent in logical tasks. To bridge this gap, we propose a Neuro-Symbolic architecture that integrates a Logical Knowledge Graph (LKG) with dynamic solver routing. Specifically, we introduce an ontology-based LKG that treats logical rules and constraints as first-class topological nodes, enabling explicit modeling of dependencies extracted from text. We further design a Logic Router to dynamically dispatch tasks to the optimal symbolic engine, which is supported by a topology-aware hybrid retrieval mechanism. Experimental results on logical reasoning benchmarks demonstrate that our framework significantly outperforms state-of-the-art prompting and RAG baselines, delivering higher accuracy and verifiable reasoning paths.
Standard dense retrievers lack a native calculus for multi-atom logical constraints. We introduce Neuro-Symbolic Fuzzy Logic (NSFL), a framework that adapts formal t-norms and t-conorms to neural embedding spaces without requiring retraining. NSFL operates as a first-order hybrid calculus: it anchors logical operations on isolated zero-order similarity scores while actively steering representations using Neuro-Symbolic Deltas (NS-Delta) -- the first-order marginal differences derived from contextual fusion. This preserves pure atomic meaning while capturing domain reliance, preventing the representation collapse and manifold escape endemic to traditional geometric baselines. For scalable real-time retrieval, Spherical Query Optimization (SQO) leverages Riemannian optimization to project these fuzzy formulas into manifold-stable query vectors. Validated across six distinct encoder configurations and two modalities (including zero-shot and SOTA fine-tuned models), NSFL yields mAP improvements up to +81%. Notably, NSFL provides an additive 20% average and up to 47% boost even when applied to encoders explicitly fine-tuned for logical reasoning. By establishing a training-free, order-aware calculus for high-dimensional spaces, this framework lays the foundation for future dynamic scaling and learned manifold logic.
Large pretrained language models and neural reasoning systems have advanced many natural language tasks, yet they remain challenged by knowledge-intensive queries that require precise, structured multi-hop inference. Knowledge graphs provide a compact symbolic substrate for factual grounding, but integrating graph structure with neural models is nontrivial: naively embedding graph facts into prompts leads to inefficiency and fragility, while purely symbolic or search-heavy approaches can be costly in retrievals and lack gradient-based refinement. We introduce NeuroSymActive, a modular framework that combines a differentiable neural-symbolic reasoning layer with an active, value-guided exploration controller for Knowledge Graph Question Answering. The method couples soft-unification style symbolic modules with a neural path evaluator and a Monte-Carlo style exploration policy that prioritizes high-value path expansions. Empirical results on standard KGQA benchmarks show that NeuroSymActive attains strong answer accuracy while reducing the number of expensive graph lookups and model calls compared to common retrieval-augmented baselines.