scholarly journals Non-simply-laced symmetry algebras in F-theory on singular spaces

2018 ◽  
Vol 2018 (9) ◽  
Author(s):  
Antonella Grassi ◽  
James Halverson ◽  
Cody Long ◽  
Julius L. Shaneson ◽  
Jiahua Tian
2002 ◽  
Vol 04 (04) ◽  
pp. 725-750 ◽  
Author(s):  
CHIKAKO MESE

Recent developments extend much of the known theory of classical harmonic maps between smooth Riemannian manifolds to the case when the target is a metric space of curvature bounded from above. In particular, the existence and regularity theorems for harmonic maps into these singular spaces have been successfully generalized. Furthermore, the uniqueness of harmonic maps is known when the domain has a boundary (with a smallness of image condition if the target curvature is bounded from above by a positive number). In this paper, we will address the question of uniqueness when the domain space is without a boundary in two cases: one, when the curvature of the target is strictly negative and two, for a map between surfaces with nonpositive target curvature.


Author(s):  
Daniel Greb ◽  
Stefan Kebekus ◽  
Thomas Peternell

AbstractBased on a recent extension theorem for reflexive differential forms, that is, regular differential forms defined on the smooth locus of a possibly singular variety, we study the geometry and cohomology of sheaves of reflexive differentials.First, we generalise the extension theorem to holomorphic forms on locally algebraic complex spaces. We investigate the (non-)existence of reflexive pluri-differentials on singular rationally connected varieties, using a semistability analysis with respect to movable curve classes. The necessary foundational material concerning this stability notion is developed in an appendix to the paper. Moreover, we prove that Kodaira–Akizuki–Nakano vanishing for sheaves of reflexive differentials holds in certain extreme cases, and that it fails in general. Finally, topological and Hodge-theoretic properties of reflexive differentials are explored.


2000 ◽  
Vol 2000 (10) ◽  
pp. 033-033 ◽  
Author(s):  
Eric Bergshoeff ◽  
Renata Kallosh ◽  
Antoine Van Proeyen
Keyword(s):  

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