The Tait conjectures are three conjectures made by 19th-century mathematician Peter Guthrie Tait in his study of knots. [1] The Tait conjectures involve concepts in knot theory such as alternating knots, chirality, and writhe. All of the Tait conjectures have been solved, the most recent being the Flyping conjecture.
Tait came up with his conjectures after his attempt to tabulate all knots in the late 19th century. As a founder of the field of knot theory, his work lacks a mathematically rigorous framework, and it is unclear whether he intended the conjectures to apply to all knots, or just to alternating knots. It turns out that most of them are only true for alternating knots. [2] In the Tait conjectures, a knot diagram is called "reduced" if all the "isthmi", or "nugatory crossings" have been removed.
Tait conjectured that in certain circumstances, crossing number was a knot invariant, specifically:
Any reduced diagram of an alternating link has the fewest possible crossings.
In other words, the crossing number of a reduced, alternating link is an invariant of the knot. This conjecture was proved by Louis Kauffman, Kunio Murasugi (村杉 邦男), and Morwen Thistlethwaite in 1987, using the Jones polynomial. [3] [4] [5] A geometric proof, not using knot polynomials, was given in 2017 by Joshua Greene. [6]
A second conjecture of Tait:
An amphicheiral (or acheiral) alternating link has zero writhe.
This conjecture was also proved by Kauffman and Thistlethwaite. [3] [7]
The Tait flyping conjecture can be stated:
Given any two reduced alternating diagrams and of an oriented, prime alternating link: may be transformed to by means of a sequence of certain simple moves called flypes . [8]
The Tait flyping conjecture was proved by Thistlethwaite and William Menasco in 1991. [9] The Tait flyping conjecture implies some more of Tait's conjectures:
Any two reduced diagrams of the same alternating knot have the same writhe.
This follows because flyping preserves writhe. This was proved earlier by Murasugi and Thistlethwaite. [10] [7] It also follows from Greene's work. [6] For non-alternating knots this conjecture is not true; the Perko pair is a counterexample. [2] This result also implies the following conjecture:
Alternating amphicheiral knots have even crossing number. [2]
This follows because a knot's mirror image has opposite writhe. This conjecture is again only true for alternating knots: non-alternating amphichiral knot with crossing number 15 exist. [11]
In the mathematical field of topology, knot theory is the study of mathematical knots. While inspired by knots which appear in daily life, such as those in shoelaces and rope, a mathematical knot differs in that the ends are joined so it cannot be undone, the simplest knot being a ring. In mathematical language, a knot is an embedding of a circle in 3-dimensional Euclidean space, . Two mathematical knots are equivalent if one can be transformed into the other via a deformation of upon itself ; these transformations correspond to manipulations of a knotted string that do not involve cutting it or passing through itself.
Peter Guthrie Tait FRSE was a Scottish mathematical physicist and early pioneer in thermodynamics. He is best known for the mathematical physics textbook Treatise on Natural Philosophy, which he co-wrote with Lord Kelvin, and his early investigations into knot theory.
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In knot theory, the Kauffman polynomial is a 2-variable knot polynomial due to Louis Kauffman. It is initially defined on a link diagram as
Morwen Bernard Thistlethwaite is a knot theorist and professor of mathematics for the University of Tennessee in Knoxville. He has made important contributions to both knot theory and Rubik's Cube group theory.
William W. Menasco is a topologist and a professor at the University at Buffalo. He is best known for his work in knot theory.
In the mathematical theory of knots, a flype is a kind of manipulation of knot and link diagrams used in the Tait flyping conjecture. It consists of twisting a part of a knot, a tangle T, by 180 degrees. Flype comes from a Scots word meaning to fold or to turn back. Two reduced alternating diagrams of an alternating link can be transformed to each other using flypes. This is the Tait flyping conjecture, proven in 1991 by Morwen Thistlethwaite and William Menasco.
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Hernando Burgos Soto is a Canadian writer and mathematician, professor of mathematics at George Brown College. He is the author of several math papers in which he introduced some mathematics concepts and extended to tangles some celebrated results of knot theory about the Khovanov homology and the Jones polynomial. During his career as a mathematician, his interests have included Mathematical Statistics, Knot Theory, Algebraic Topology and more recently Mathematical Finance. He is comfortable writing in English and Spanish. When writing in Spanish, he works in the area of prose fiction writing short stories. Some of his short stories were published at the website Cuentos y Cuentos.