Dirk Kussin - Technische Universität Berlin
Real tubular curves

We give a short review about the construction and the classification
of the tubular curves and the elliptic curves over the field of real
numbers. These together can be considered as the 39 (families of) flat
noncommutative 2-orbifolds. The 17 of them which are actually
commutative correspond to the wallpaper patterns.