We reformulate Optimal Transport Conditional Flow Matching (OT-CFM), a class of dynamical generative models, showing that it admits an exact proximal formulation via an extended Brenier potential, without assuming that the target distribution has a density. In particular, the mapping to recover the target point is exactly given by a proximal operator, which yields an explicit proximal expression of the vector field. We also discuss the convergence of minibatch OT-CFM to the population formulation as the batch size increases. Finally, using second epi-derivatives of convex potentials, we prove that, for manifold-supported targets, OT-CFM is terminally normally hyperbolic: after time rescaling, the dynamics contracts exponentially in directions normal to the data manifold while remaining neutral along tangential directions.
翻译:我们重新表述了最优传输条件流匹配(OT-CFM)——一类动态生成模型,证明其可通过扩展的Brenier势函数获得精确的邻近算子表述,且无需假设目标分布具有密度。特别地,恢复目标点的映射恰好由邻近算子给出,这导出了向量场的显式邻近表达式。我们还讨论了小批量OT-CFM随着批量增大向总体表述的收敛性。最后,利用凸势函数的二阶上图导数,我们证明了对于流形支撑的目标分布,OT-CFM具有终端正规双曲性:经过时间重标度后,动力学在垂直于数据流形的方向上呈指数收缩,而在切向方向上保持中性。