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3 unusual facts about Perko pair


Knot tabulation

In 1974 Perko discovered a duplication in the Tait-Little tables, called the Perko pair.

Perko pair

This duplication had been missed by John Horton Conway several years before in his knot table and subsequently found its way into Rolfsen's table.

Tait conjectures

For non-alternating knots this conjecture is not true, assuming so lead to the duplication of the Perko pair, because it has two reduced projections with different writhe.



see also