Dehn himself was a particularly enthusiastic advocate of group diagrams . 戴恩本人就特别热衷的群图解的倡导者。
2.
Dehn showed how a presentation of the group of a knot can be read off from a projection of the knot into a plane . Dehn指明了一个纽结的群的一种表示如何由该纽结在平面上的一个投影看出。
3.
Dehn showed how a presentation of the group of a knot can be read off from a projection of the knot into a plane Dehn指明了一个纽结的群的一种表示如何由该纽结在平面上的一个投影看出。
