scholarly journals On the monomial birational maps of the projective space

2003 ◽  
Vol 75 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Gérard Gonzalez-Sprinberg ◽  
Ivan Pan
Keyword(s):  
Projective Space ◽  
Group Structure ◽  
Cremona Transformations ◽  
Birational Maps

We describe the group structure of monomial Cremona transformations. It follows that every element of this group is a product of quadratic monomial transformations, and geometric descriptions in terms of fans.

scholarly journals Circle of Sarkisov Links on a Fano 3-Fold

2016 ◽  
Vol 60 (1) ◽  
pp. 1-16
Author(s):  
Hamid Ahmadinezhad ◽  
Francesco Zucconi
Keyword(s):  
Projective Space ◽  
Weighted Projective Space ◽  
Birational Maps

AbstractFor a general Fano 3-fold of index 1 in the weighted projective space ℙ(1, 1, 1, 1, 2, 2, 3) we construct two new birational models that are Mori fibre spaces in the framework of the so-called Sarkisov program. We highlight a relation between the corresponding birational maps, as a circle of Sarkisov links, visualizing the notion of relations in the Sarkisov program.

Quarto-quartic birational maps of ℙ3(ℂ)

2017 ◽  
Vol 28 (05) ◽  
pp. 1750037
Author(s):  
Julie Déserti ◽  
Frédéric Han
Keyword(s):  
Projective Space ◽  
Complex Projective Space ◽  
Birational Maps ◽  
Dimension Formula ◽  
Trigonal Curves ◽  
Irreducible Components ◽  
Genus Formula ◽  
Complex Projective

We construct a determinantal family of quarto-quartic transformations of a complex projective space of dimension [Formula: see text] from trigonal curves of degree [Formula: see text] and genus [Formula: see text]. Moreover, we show that the variety of [Formula: see text]-birational maps of [Formula: see text] has at least four irreducible components and describe three of them.

Some effects of unequal distribution of information in a wheel group structure.

1954 ◽  
Vol 49 (4, Pt.1) ◽  
pp. 554-556 ◽  
Author(s):  
J. C. Gilchrist ◽  
Marvin E. Shaw ◽  
L. C. Walker
Keyword(s):  
Group Structure ◽  
Unequal Distribution

A performative network theory of attitudes

2020 ◽  
Author(s):  
Michael Quayle
Keyword(s):  
Attitude Change ◽  
Network Structure ◽  
Network Theory ◽  
Social Group ◽  
Group Structure ◽  
Social Identities ◽  
Bipartite Network ◽  
Identity Change ◽  
Multilayer Network ◽  
Dynamic Phenomena

In this paper I propose a network theory of attitudes where attitude agreements and disagreements forge a multilayer network structure that simultaneously binds people into groups (via attitudes) and attitudes into clusters (via people who share them). This theory proposes that people have a range of possible attitudes (like cards in a hand) but these only become meaningful when expressed (like a card played). Attitudes are expressed with sensitivity to their potential audiences and are socially performative: when we express attitudes, or respond to those expressed by others, we tell people who we are, what groups we might belong to and what to think of us. Agreement and disagreement can be modelled as a bipartite network that provides a psychological basis for perceived ingroup similarity and outgroup difference and, more abstractly, group identity. Opinion-based groups and group-related opinions are therefore co-emergent dynamic phenomena. Dynamic fixing occurs when particular attitudes become associated with specific social identities. The theory provides a framework for understanding identity ecosystems in which social group structure and attitudes are co-constituted. The theory describes how attitude change is also identity change. This has broad relevance across disciplines and applications concerned with social influence and attitude change.

The Centralizer

2018 ◽  
Author(s):  
Ercüment H. Ortaçgil
Keyword(s):  
Lie Group ◽  
Group Structure ◽  
Diffeomorphism Group ◽  
Group Diff ◽  
Local Solutions

The pseudogroup of local solutions in Chapter 3 defines another pseudogroup by taking its centralizer inside the diffeomorphism group Diff(M) of a manifold M. These two pseudogroups define a Lie group structure on M.

Sign in / Sign up

Export Citation Format

Share Document