2019/07/29 by Shi, Yuguang, Wang, Wenlong, Wei, Guodong +1
#Differential Geometry (math.DG) #FOS: Mathematics #Primary 53C20 #Secondary 83C99
paper · doi:10.48550/arxiv.1907.12173
In the first part of this paper, we consider the problem of fill-in of nonnegative scalar curvature (NNSC) metrics for a triple of Bartnik data (Σ,γ,H). We prove that given a metric γ on Sn-1 (3≤ n≤ 7), (Sn-1,γ,H) admits no fill-in of NNSC metrics provided the prescribed mean curvature H is large enough (Theorem \refThm: no fillin nonnegative scalar 2). Moreover, we prove that if γ is a positive scalar curvature (PSC) metric isotopic to the standard metric on Sn-1, then the much weaker condition that the total mean curvature ∫\mathbf Sn-1H \mathrm dμγ is large enough rules out NNSC fill-ins, giving an partially affirmative answer to a conjecture by Gromov (see P. 23 in \citeGromov4). In the second part of this paper, we investigate the θ-invariant of Bartnik data and obtain some sufficient conditions for the existence of PSC fill-ins.