The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
A 2-knot is a surface in R4 that is homeomorphic to S2, the standard sphere in 3-space. A ribbon 2-knot is a 2-knot obtained from m 2-spheres in R4 by connecting them with m−1 annuli. Let K2 be a ribbon 2-knot. The ribbon crossing number, denoted by r-cr(K2) is a numerical invariant of the ribbon 2-knot K2. It is known that the degree of the Alexander polynomial of K2 is less than or equal to r-cr(K2)...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.