Diagrammatic unknotting of knots and links in the projective space
Abstract
Description
In the classical knot theory there is a well-known notion of descending diagram. From an arbitrary diagram one can easily obtain, by some crossing changes, a descending diagram which is a diagram of the unknot or unlink. In this paper the notion of descending diagram for knots and links in the real space is extended to the case of nonoriented knots and links in the projective space. It is also shown that this notion cannot be extended to oriented links.
15 pages, 9 figures, error corrected on page 9
15 pages, 9 figures, error corrected on page 9