Wirtinger presentation of knot groups

E427429

The Wirtinger presentation of knot groups is a classical method in knot theory that describes the fundamental group of a knot complement using generators and relations derived from a knot diagram.

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Label Occurrences
Wirtinger presentation of knot groups canonical 1

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Statements (48)

Predicate Object
instanceOf construction in knot theory
group presentation technique
mathematical method
appliesTo knot groups
associates group element to each oriented arc between undercrossings
assumes knot complement path-connected
knot embedded in 3-sphere
basedOn Wirtinger generators NERFINISHED
Wirtinger relations NERFINISHED
captures isotopy type of the knot via its group
category presentation of fundamental groups
computationalUse input for computer algebra systems in knot theory
constructionMethod combinatorial
diagrammatic
contrastsWith geometric descriptions of knot complements
describes fundamental group of a knot complement
encodes over-under crossing information as relations
ensures presentations from equivalent diagrams define isomorphic groups
field algebraic topology
geometric topology
knot theory
generalizesTo Wirtinger presentation of link groups
generatorOrigin arcs of the knot diagram
gives finite presentation of the knot group
historicalPeriod early 20th century
independentOf particular choice of diagram up to isomorphism
input planar diagram of an oriented knot
invariantUnder Reidemeister moves NERFINISHED
isAlgorithmic true
namedAfter Wilhelm Wirtinger NERFINISHED
output finite group presentation
relatedTo Dehn presentation of knot groups
fundamental group of the complement S^3 \ K
van Kampen theorem NERFINISHED
relationOrigin crossings of the knot diagram
reliesOn planar projection of the knot
requires choice of orientation on the knot
teachingUse introductory tool for explaining knot groups
typicalRelationForm conjugation relation at each crossing
usedFor computing Alexander invariants
computing further invariants from the knot group
computing knot group
computing representations of knot groups
distinguishing non-equivalent knots
uses knot diagram
worksFor links as well as knots
yields one generator for each arc of the diagram
one relation for each crossing of the diagram

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Referenced by (1)

Full triples — surface form annotated when it differs from this entity's canonical label.

Wilhelm Wirtinger notableFor Wirtinger presentation of knot groups