Kuvaus
Alkuperäiskieli  englanti 

Myöntävä instituutio 

Valvoja/neuvonantaja 

Myöntöpäivämäärä  26 toukokuuta 2017 
Julkaisupaikka  Helsinki 
Kustantaja  
Painoksen ISBN  9789515131829 
Sähköinen ISBN  9789515131836 
Tila  Julkaistu  26 toukokuuta 2017 
OKMjulkaisutyyppi  G5 Tohtorinväitöskirja (artikkeli) 
Tieteenalat
 111 Matematiikka
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Monodromy representations of branched covering maps between manifolds. / Aaltonen, Saga Martina.
Helsinki : University of Helsinki, 2017. 15 s.Tutkimustuotos: Opinnäyte › Väitöskirja › Artikkelikokoelma
TY  THES
T1  Monodromy representations of branched covering maps between manifolds
AU  Aaltonen, Saga Martina
PY  2017/5/26
Y1  2017/5/26
N2  A monodromy representation represents a branched covering map between manifolds as a factor of an orbit map. This factorization arises from the monodromy of the branched covering map. We call the domain of the orbit map the monodromy space of the branched covering map. In this thesis a manifold is a connected second countable Hausdorff space that is locally homeomorphic to the Euclidean space. A branched covering map between manifolds is an open, continuous and discrete map. A branch point of a branched covering map is a point at which the map fails to be a local homeomorphism, and the branch set is the set of branch points. The first research question of this thesis considers new existence results of monodromy representations: In what extent does Bersteins and Edmonds construction of a monodromy representation generalize to branched covering maps between manifolds? In article [A] we first consider a class of branched covering maps between manifolds that is natural for the construction. Then we introduce a characterization for the existence of a monodromy representation within this class of maps. The second research question concerns the properties of the monodromy space: What properties can we expect from the monodromy space as a topological space? The monodromy space is a locally connected Hausdorff space by construction. In article [A] we provide an example to show that the monodromy space is not in general a locally compact space. In article [C] we provide further examples to show that a monodromy space that is a locally compact space, is not in general a manifold, a locally contractible space or a cohomology manifold. The third research question concerns new applications of monodromy representations in the study of branched covering maps between manifolds: What consequences does the existence of a monodromy representation have on the branch set of a branched covering map between manifolds? The branch set has by Väisälä codimension more or equal to two. A classical conjecture of Church and Hemmingsen states that the codimension of the branch set is strictly two for a branched covering map from the three sphere to a three sphere. We show together with Pankka in article [B] two partial results in the direction of this conjecture.
AB  A monodromy representation represents a branched covering map between manifolds as a factor of an orbit map. This factorization arises from the monodromy of the branched covering map. We call the domain of the orbit map the monodromy space of the branched covering map. In this thesis a manifold is a connected second countable Hausdorff space that is locally homeomorphic to the Euclidean space. A branched covering map between manifolds is an open, continuous and discrete map. A branch point of a branched covering map is a point at which the map fails to be a local homeomorphism, and the branch set is the set of branch points. The first research question of this thesis considers new existence results of monodromy representations: In what extent does Bersteins and Edmonds construction of a monodromy representation generalize to branched covering maps between manifolds? In article [A] we first consider a class of branched covering maps between manifolds that is natural for the construction. Then we introduce a characterization for the existence of a monodromy representation within this class of maps. The second research question concerns the properties of the monodromy space: What properties can we expect from the monodromy space as a topological space? The monodromy space is a locally connected Hausdorff space by construction. In article [A] we provide an example to show that the monodromy space is not in general a locally compact space. In article [C] we provide further examples to show that a monodromy space that is a locally compact space, is not in general a manifold, a locally contractible space or a cohomology manifold. The third research question concerns new applications of monodromy representations in the study of branched covering maps between manifolds: What consequences does the existence of a monodromy representation have on the branch set of a branched covering map between manifolds? The branch set has by Väisälä codimension more or equal to two. A classical conjecture of Church and Hemmingsen states that the codimension of the branch set is strictly two for a branched covering map from the three sphere to a three sphere. We show together with Pankka in article [B] two partial results in the direction of this conjecture.
KW  111 Mathematics
M3  Doctoral Thesis
SN  9789515131829
PB  University of Helsinki
CY  Helsinki
ER 