4arXiv cs.CL (Computation and Language)·
RSF-GLLM: Differentiable graph reasoning framework for multi-hop knowledge graph QA
RSF-GLLM is a new framework for multi-hop question answering over knowledge graphs that decouples differentiable graph reasoning from LLM-based answer generation. The core Recurrent Soft-Flow (RSF) module uses a GRU-guided query updater with dynamic gating to traverse semantically dissimilar bridge nodes, with flow sparsity regularization guaranteeing convergence to discrete reasoning paths. Extracted paths are textualized to fine-tune an LLM, grounding generation in factual graph topology. Experiments on WebQSP and CWQ benchmarks show competitive accuracy with improved inference efficiency over LLM-heavy baselines.
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ExpRL: RL-based mid-training using human QA data as reward scaffolds for LLM reasoning
ExpRL proposes an automated approach to LLM mid-training that replaces manually curated reasoning traces with large corpora of human-written QA data used as reward scaffolds rather than imitation targets. Reference solutions are hidden from the policy and used only to construct problem-specific grading rubrics, enabling dense process-level rewards that reinforce partial progress and intermediate reasoning steps. On challenging math reasoning benchmarks, ExpRL outperforms SFT, sparse-reward GRPO, and self-distillation as an RL initialization strategy, with additional mixed-domain experiments suggesting broader applicability.
Theoretical framework for grounding LLM reasoning under incomplete knowledge graph evidence
A new arXiv preprint develops a formal theoretical framework for understanding how LLMs reason when guided by incomplete knowledge graphs. The authors introduce constructs including entity anchors, typed relation residuals, path energies, and support regions, and prove that under open-world incompleteness no hard rule can simultaneously reject all false unsupported trajectories while retaining all true-but-unobserved ones. Soft grounding is characterized as a KL-regularized deformation of the LLM prior, with hard conditioning as an infinite-penalty limit. The framework yields stability bounds under evidence perturbations and has implications for GraphRAG, KGQA, graph agents, constrained decoding, and faithful generation.
REAL: Reasoning-enhanced temporal graph framework for LLM long-term memory management
REAL is a new framework that represents LLM conversational memory as a temporal, confidence-aware directed property graph, where atomic facts carry validity intervals, confidence scores, and exploration intent labels. It addresses three limitations of prior memory systems: flat text structures, destructive overwrites of evolving facts, and passive retrieval. The system uses non-destructive temporal updates, semantic evaluator-guided hybrid beam search, and counterfactual inference to repair incomplete retrieval states. Experiments show a 22.72% average improvement over flat-text, graph-based, and existing memory baselines.
RASER: Recoverability-Aware Selective Escalation Router for Multi-Hop Question Answering
RASER introduces a family of lightweight routers that decide whether to escalate retrieval complexity for multi-hop QA without making additional LLM calls. Built on top of one-shot RAG using six derived features, RASER-2 and RASER-3 route queries to progressively more expensive retrieval strategies (PRUNE, IRCoT) only when needed. Across six LLMs and three benchmarks, the routers match SOTA F1 while consuming only 41-49% of the tokens required by always-escalating baselines.
GraphPO: Graph-based Policy Optimization reduces redundancy in LLM reasoning RL
GraphPO is a new reinforcement learning framework that represents reasoning rollouts as directed acyclic graphs rather than independent chains or trees, merging semantically equivalent reasoning paths into equivalence classes to share suffixes and reduce redundant exploration. The approach assigns efficiency advantages to incoming edges and correctness advantages to outgoing edges, deriving process supervision from outcome rewards. Experiments on three LLMs across reasoning and agentic search benchmarks show consistent improvements over chain- and tree-based baselines under equal token or response budgets. The method also provides theoretical guarantees on reduced advantage-estimation variance.
LongTraceRL: Reinforcement Learning for Long-Context Reasoning via Search Agent Trajectories and Rubric Rewards
LongTraceRL is a new RL training framework for improving long-context reasoning in LLMs, addressing limitations of existing RLVR methods. It constructs challenging training data using multi-hop questions from knowledge graph random walks and tiered distractors derived from search agent trajectories (high-confusability: read but uncited; low-confusability: seen but unopened). A rubric reward provides entity-level process supervision along reasoning chains, applied only to correct responses to prevent reward hacking. Experiments across three LLMs (4B–30B parameters) on five long-context benchmarks show consistent improvements over strong baselines.
KG grounding helps LLMs only for out-of-training knowledge: controlled clinical QA study
A new arXiv paper investigates when knowledge-graph (KG) grounding improves LLM performance on clinical question answering, finding that structured KG retrieval over the public biomedical graph PrimeKG provides no meaningful improvement on MedQA (all deltas ≤3.4) because the relevant facts are already in the model's training data. On synthetic counterfactual and hybrid benchmarks containing genuinely novel facts, the same pipeline lifts out-of-training accuracy from chance to ~100%. The paper also reproduces and partially corrects a recent Nature Medicine study on frontier LLMs vs. clinical RAG tools, flagging a score-deflating grader bug and clarifying that the reported ~88 HealthBench score reflects the Consensus variant, not full HealthBench (~46-47). The core finding — that RAG/KG grounding pays off only when the decisive fact is outside the model's training distribution — has direct implications for when retrieval augmentation is worth deploying.
Peak-Then-Collapse: RLVR Tool-Use Failures on Knowledge-Graph APIs
This paper investigates RLVR-based tool-use training (GRPO on Qwen2.5-7B-Instruct) on a minimal knowledge-graph API (Freebase over Complex WebQuestions) and documents a 'peak-then-collapse' pattern where tool-grounded answer rates rise then fall to zero within 50 steps, replicated across four seeds and seven reward designs. The authors identify a key structural difference between knowledge-graph APIs and other tool types (Python, web search, JSON): sparse, non-natural-language feedback signals (e.g., empty brackets '[]') prevent the model from recovering via pretraining-familiar error signals. A direct oracle ablation shows relation selection is not the bottleneck—95.4% of errors are retrieval-composition failures—and self-distillation reaches 40% EM at 7B, with capacity scaling to 14B yielding only marginal gains, suggesting an interface-bound ceiling.