10 papers
Discriminating Fixture Coverage in Agent-Infrastructure Verification Suites
Xin Xu, Siru Tao
Invariant suites and runtime monitors increasingly gate agent deployment decisions, and the evidence offered for any particular suite is almost always a single observation: it pass…
Hard-Gate Candidacy in a Deployed Validator Suite
Xin Xu
Before a validator can be promoted to a hard gate on a deployment pipeline, it has to be shown that its firing separates outputs that reach users in working order from those that d…
The Oversight Gap: What LLM Safety Monitors Miss, and Why It Is Not Capability
Xin Xu
Several properties safety monitors are asked to certify, among them cross-tenant noninterference, sandbagging and evaluation awareness, are 2-safety hyperproperties, witnessed only…
Teaching Vision-Language Models to Use the Scale They Are Given: Label-Free Equivariance Training for Metric Physical Reasoning
Kaizhen Tan, Yang Feng, Heqing Du +3
Metric questions about video, such as the speed of a moving object, require a vision-language model to convert visual measurements into physical units using a real-world reference…
Reasoning Shortcuts and Value Symmetries: What Symmetry Permits, Architecture Realizes, and Optimization Selects
Xin Xu
Reasoning shortcuts are rule solutions that reach correct predictions through unintended concepts. A recent framework of Takemura, Inoue, and Nishino analyzes them through an autom…
Beyond Multimodal Alignment: Shared Physical Representations Across Sensors and Action Orders
Kaizhen Tan, Xin Xu, Siru Tao +4
Multimodal world models are often evaluated by whether different sensors produce similar representations. However, similar representations do not necessarily imply that the models…
Renaming or Tightness: Enforcing Disjunctive Information Flow Policies
Xin Xu, Siru Tao, Kaizhen Tan
A disjunctive policy allows a value to depend on at most one of two secrets and never on both: an analyst may consult one client's file or the other's, a share of a split secret ma…
What Can Latent World Models Know? Physical Information in Multimodal Predictive Representations
Kaizhen Tan, Sizhe Xu, Xin Xu +6
A central premise of latent world models is that predicting the future encourages representations to internalize the physics of their environment. We ask which physical quantities…
Collusion with Competitive Marginals: Price-Level Audits Are Blind by Construction
Xin Xu, Chengrui Wu, Jiayu Lu +3
Empirical work on algorithmic collusion asks one question of the data: are prices supracompetitive? We show this can be answered "no" by a conspiracy that is nonetheless profitable…
Automorphism-Induced Non-Canonicity in Top-k Explanations of Graph Neural Networks
Xin Xu, Siru Tao, Kaizhen Tan
A gradient-based GNN explainer given a molecule with two chemically equivalent nitro groups assigns them attribution scores that are equal to the last bit. It cannot do otherwise:…