On the Crossing Number of K-n without Computer Assistance

摘要

We present several general results about drawings of K-n, as a beginning to trying to determine its crossing number. As application, we give a complete proof that the crossing number of K-9 is 36 and that all drawings in one large, natural class of drawings of K-11 have at least 100 crossings. (C) 2015 Wiley Periodicals, Inc.