Separable Closure and the Fundamental Groupoid

2015 ◽  
Vol 22 (4) ◽  
Author(s):  
Ilia Pirashvili

AbstractIn this paper we prove that for good topological spaces the assignment


2019 ◽  
Vol 525 ◽  
pp. 416-434
Author(s):  
Stefan Schröer
Keyword(s):  

2001 ◽  
Vol 27 (3) ◽  
pp. 131-140 ◽  
Author(s):  
Osman Mucuk ◽  
İlhan İçen

A groupoid is a small category in which each morphism has an inverse. A topological groupoid is a groupoid in which both sets of objects and morphisms have topologies such that all maps of groupoid structure are continuous. The notion of monodromy groupoid of a topological groupoid generalizes those of fundamental groupoid and universal cover. It was earlier proved that the monodromy groupoid of a locally sectionable topological groupoid has the structure of a topological groupoid satisfying some properties. In this paper a similar problem is studied for compatible locally trivial topological groupoids.


1998 ◽  
Vol 08 (02) ◽  
pp. 141-152 ◽  
Author(s):  
N. D. Gilbert

We consider properties of a 2-complex associated by Squier to a monoid presentation. We show that the fundamental groupoid admits a monoid structure, and we establish a relationship between its group completion and the fundamental group of the 2-complex. We also treat a modified complex, due to Pride, for monoid presentations of groups, and compute the structure of the fundamental groupoid in this setting.


1997 ◽  
Vol 07 (03) ◽  
pp. 313-338 ◽  
Author(s):  
Vesna Kilibarda

In this work we enrich the geometric method of semigroup diagrams to study semigroup presentations. We introduce a process of reduction on semigroup diagrams which leads to a natural way of multiplying semigroup diagrams associated with a given semigroup presentation. With respect to this multiplication the set of reduced semigroup diagrams is a groupoid. The main result is that the groupoid [Formula: see text] of reduced semigroup diagrams over the presentation S = <X:R> may be identified with the fundamental groupoid γ (KS) of a certain 2-dimensional complex KS. Consequently, the vertex groups of the groupoid [Formula: see text] are isomorphic to the fundamental groups of the complex KS. The complex we discovered was first considered in the paper of Craig Squier, published only recently. Steven Pride has also independently defined a 2-dimensional complex isomorphic to KS in relation to his work on low-dimensional homotopy theory for monoids. Some structural information about the fundamental groups of the complex KS are presented. The class of these groups contains all finitely generated free groups and is closed under finite direct and finite free products. Many additional results on the structure of these groups may be found in the paper of Victor Guba and Mark Sapir.


2021 ◽  
Author(s):  
Arthur F. Ramos ◽  
Ruy J. G. B. de Queiroz ◽  
Anjolina G. de Oliveira

Using computational paths as the fundamental concept, we show that we can leverage Category Theory to propose the concept of fundamental groupoid of a type.


1976 ◽  
Vol 28 (4) ◽  
pp. 774-787 ◽  
Author(s):  
Michael Fried ◽  
Moshe Jarden

For a field M we denote by Ms and respectively the separable closure and the algebraic closure of M. If F is a variety which is defined over M, then we denote by V(M) the set of all if-rational points of V. M is said to be pseudo-algebraically closed (PAC) field, if V(M) ≠ θ for every non-void abstract variety V defined over M. It can be shown that then is dense in V(M) in the Zariski M -topology.


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