Deep Distributional Learning with Non-crossing Quantile Network
This addresses a technical issue in distributional learning for researchers and practitioners, but appears incremental as it builds on existing methods with a specific improvement.
The paper tackles the problem of quantile crossing in conditional distribution learning by introducing a non-crossing quantile network that ensures monotonic distributions, and demonstrates its effectiveness in applications like quantile regression and distributional RL.
In this paper, we introduce a non-crossing quantile (NQ) network for conditional distribution learning. By leveraging non-negative activation functions, the NQ network ensures that the learned distributions remain monotonic, effectively addressing the issue of quantile crossing. Furthermore, the NQ network-based deep distributional learning framework is highly adaptable, applicable to a wide range of applications, from classical non-parametric quantile regression to more advanced tasks such as causal effect estimation and distributional reinforcement learning (RL). We also develop a comprehensive theoretical foundation for the deep NQ estimator and its application to distributional RL, providing an in-depth analysis that demonstrates its effectiveness across these domains. Our experimental results further highlight the robustness and versatility of the NQ network.