标题： 关于退化的相边界 显示英文标题

标题： On the degenerate phase boundaries

摘要： 退简和非退简区域之间的相界结构在Ashtekar引力中由Bengtsson和Jacobson进行了研究，他们推测“相界”应该总是零性的。 在本文中，我们将映射语言中的重参数化过程重新表述，并区分相界与其像。 结果表明，像必须是零性的，而相界的零性需要更合适的判据。 显示英文摘要

摘要： The structure of the phase boundary between degenerate and non-degenerate regions in Ashtekar's gravity has been studied by Bengtsson and Jacobson who conjectured that the "phase boundary" should always be null. In this paper, we reformulate the reparametrization procedure in the mapping language and distinguish a phase boundary from its image. It is shown that the image has to be null, while the nullness of the phase boundary requries more suitable criterion.