科研之友
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摘要
The sheet number of a 2-knot is a quantity which reflects the complexity of the knotting in 4-space. The aim of this note is to determine the sheet numbers of the 2- and 3-twist-spun trefoils. For this purpose, we give a lower bound of the sheet number by the quandle cocycle invariant of a 2-knot, and an upper bound by the crossing number of a 1-knot.
- 出版日期2010-3
