2 citations · 3 across the 4 of their papers we have counts for
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Conformally invariant rigidity theorems on four-manifolds with boundary
Siyi Zhang
In the article we introduce new conformal and smooth invariants on compact, oriented four-manifolds with boundary. In the first part, we show that "positivity" conditions on these…
Rigidity for Bach-flat metrics on manifolds with boundary and applications
Matthew J. Gursky, Siyi Zhang
In the article we consider Bach-flat metrics on four-manifolds with boundary, with conformally invariant boundary conditions. We show that such metrics arise naturally as critical…
Some conformally invariant gap theorems for Bach-flat 4-manifolds
Siyi Zhang
Around 2007, A. Chang, J. Qing, and P. Yang proved a conformal gap theorem for Bach-flat metrics with round sphere as the model case. In this article, we extend this result to prov…
A conformally invariant gap theorem characterizing via the Ricci flow
Sun-Yung A. Chang, Matthew Gursky, Siyi Zhang
We extend the sphere theorem of \cite{CGY03} to give a conformally invariant characterization of . In particular, we introduce a conformal invariant $β(M^4…