mapping class group of a surface造句

This means that the mapping class group of a surface is a finitely presented group.
The geometric vein in the study of Teichm黮ler space was revived following the work of William Thurston in the late seventies, who introduced a geometric compactification which he used in his study of the mapping class group of a surface.
It's difficult to find mapping class group of a surface in a sentence. 用mapping class group of a surface造句挺难的