Minimal triple point numbers of some non-orientable surface-links
Shin Satoh · Pacific Journal of Mathematics · 2001
An embedded surface in R 4 is projected into R 3 with the double point set which includes a finite number of triple points.We consider the minimal number of such triple points among all projections of embedded surfaces which are ambient isotopic to a given surface and show that for any non-negative integer N there exists a 2-component non-orientable surface in R 4 whose minimal triple point number is equal to 2N .