منابع مشابه
Holomorphic Engel Structures
Recently there has been renewed interest among differential geometers in the theory of Engel structures. We introduce holomorphic analogues of these structures, and pose the problem of classifying projective manifolds admitting them. Besides providing the basic properties of these varieties, we present two series of examples and characterize them by certain positivity conditions on the Engel st...
متن کاملExistence of Engel structures
We develop a construction of Engel structures on 4– manifolds based on decompositions of manifolds into round handles. This allows us to show that all parallelizable 4–manifolds admit an Engel structure. We also show that, given two Engel manifolds M1, M2 satisfying a certain condition on the characteristic foliations, there is an Engel structure on M1#M2#(S ×S) which is closely related to the ...
متن کاملEngel structures with trivial characteristic foliations
Engel structures on M×S and M×I are studied in this paper, where M is a 3–dimensional manifold. We suppose that these structures have characteristic line fields parallel to the fibres, S or I . It is proved that they are characterized by contact structures on the cross section M , the twisting numbers, and Legendrian foliations on both ends M × ∂I in the case of M × I . AMS Classification 57R25...
متن کاملMichael Engel
They imparted a value for individuals, the importance of humility, an enthusiasm for sharing knowledge, and an appreciation of history. Photo: Kellie K. Magill. fi eld, and poorer countries could also develop their own biotechnology approaches. This more democratic approach to agro-biotech could conceivably gain back some of the trust that giant companies like Monsanto and DuPont lost in the GM...
متن کاملChristoph Engel
A. Introduction.......................................................................................................... 2 I. The Puzzle....................................................................................................... 2 II. The Potential for Institutions ............................................................................ 3 III. Related Approaches in Literature......
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ژورنال
عنوان ژورنال: Compositio Mathematica
سال: 2020
ISSN: 0010-437X,1570-5846
DOI: 10.1112/s0010437x19007759