Results 201 to 210 of about 449,654 (297)

Peskine Sixfolds and Debarre–Voisin Fourfolds With Associated Cubic Fourfolds

open access: yesMathematische Nachrichten, EarlyView.
ABSTRACT We develop the notion of Peskine sixfolds with associated K3 surfaces and cubic fourfolds and work out numerical conditions for when these associations occur. In discriminant 24, the first family for which there is an associated cubic fourfold, we identify the cubic explicitly.
Corey Brooke   +3 more
wiley   +1 more source

Purely Coclosed G2‐Structures on Nilmanifolds—II

open access: yesMathematische Nachrichten, EarlyView.
ABSTRACT This paper completes the classification of seven‐dimensional nilpotent Lie groups endowed with a left‐invariant purely coclosed G2$\text{G}_2$‐structure, initiated in Bazzoni et al. [Mathematische Nachrichten 296 no. 6 (2023): 2236–2257], the authors provided the classification of decomposable seven‐dimensional nilpotent Lie groups and of the ...
Giovanni Bazzoni, Giorgia Petracci
wiley   +1 more source

Hilbert's Basis Theorem for Poisson Ore Extensions

open access: yesMathematische Nachrichten, EarlyView.
ABSTRACT We prove an analogue of Hilbert's basis theorem for Poisson Ore extensions and Poisson Laurent Ore extensions. We also obtain corresponding results for iterated Poisson Ore extensions and iterated Poisson Laurent Ore extensions associated to commuting Poisson‐pairs.
Per Bäck   +3 more
wiley   +1 more source

On the Nonnegative Rank of Positive Operators

open access: yesMathematische Nachrichten, EarlyView.
ABSTRACT In this paper, we introduce the concept of a nonnegative rank of a positive operator T:X→Y$T: X\rightarrow Y$ between ordered vector spaces. In the case of nonnegative matrices, our definition agrees with the standard definition of a nonnegative rank.
Roman Drnovšek, Marko Kandić
wiley   +1 more source

A Boothby–Wang Construction in Generalized Contact Geometry

open access: yesMathematische Nachrichten, EarlyView.
ABSTRACT We establish a generalized analogue of the Boothby–Wang theorem in generalized contact geometry, along with related results. We present a general method for constructing examples of generalized contact structures that are not of Poon–Wade type, and even examples that fail to be generalized contact structures.
Debjit Pal
wiley   +1 more source

Algebraic extensions in free groups

open access: yes
The aim of this paper is to unify the points of view of three recent and independent papers (Ventura 1997, Margolis, Sapir and Weil 2001 and Kapovich and Miasnikov 2002), where similar modern versions of a 1951 theorem of Takahasi were given.
Ventura, Enric   +3 more
core  

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