Alexander polynomial

E665082

The Alexander polynomial is a classical knot invariant in algebraic topology that assigns a Laurent polynomial to each knot or link, capturing essential information about its topological structure.

All labels observed (2)

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Statements (48)

Predicate Object
instanceOf Laurent polynomial-valued invariant
knot invariant
link invariant
appliesTo links with multiple components
canDistinguish some non-equivalent knots
cannotDistinguish all non-equivalent knots
captures topological information about a knot
topological information about a link
category classical knot invariant
codomain Z[t,t^{-1}]
computableFrom Seifert surface of the knot
Wirtinger presentation of the knot group
definedUsing Alexander module
Fox calculus
Seifert matrix
determinant of V - tV^T
first homology of the infinite cyclic cover
infinite cyclic cover of the knot complement
presentation matrix of the Alexander module
degreeRelatedTo twice the genus for fibered knots
dependsOn choice of knot or link
evaluationProperty Δ_K(1) = ±1 for a knot
extension multivariable Alexander polynomial for links
field algebraic topology
knot theory
generalizedBy higher-order Alexander invariants
twisted Alexander polynomial
hasAlexanderPolynomial 1
historicalPeriod introduced in the 1920s
input oriented knot
oriented link
introducedBy James Waddell Alexander II
invariantUnder Reidemeister moves
ambient isotopy of knots
namedAfter James Waddell Alexander II
normalizationProperty defined up to multiplication by ±t^n
output Laurent polynomial in one variable
relatedInvariant Conway polynomial
HOMFLY-PT polynomial
Jones polynomial
specialCaseOf multivariable Alexander polynomial
symmetryProperty Δ_K(t) = ± t^n Δ_K(t^{-1})
usedToStudy 3-manifold topology
fibered knots
knot concordance
knot genus
valueFor unknot
variable t

How these facts were elicited

Referenced by (2)

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

HOMFLY-PT polynomial generalizes Alexander polynomial
Alexander polynomial specialCaseOf multivariable Alexander polynomial
linked to: Alexander polynomial