In 2004 Oort studied the foliation on the space of $p$-divisible groups. In his theory, special leaves called central streams play an important role. It is still meaningful to investigate central streams, for example, there remain a lot of unknown things on the boundaries of central streams. In this paper, we classify the boundary components of the central stream for a Newton polygon consisting of two segments, where one slope is less than 1/2 and the other slope is greater than 1/2. Moreover we determine the generic Newton polygon of each boundary component using this classification.
"On the boundary components of central streams in the two slopes case." Kodai Math. J. 43 (2) 366 - 408, June 2020. https://doi.org/10.2996/kmj/1594313559