Curvature estimates for stable minimal surfaces with a common free boundary

The minimal surfaces meeting in triples with equal angles along a common boundary naturally arise from soap films and other physical phenomenon. They are also the natural extension of the usual minimal surface. In this paper, we consider the multiple junction surface and show the Bernstein Theorem still holds for stable multiple junction surface in some special case. The key part is to derive the $L^p$ estimate of the curvature for multiple junction surface.