LaTeX.org

I am already using amsbook.cls which is a chapter class. However the section headings do not include the chaptermark in the section title.

I would like to change the the numeration on section titles: at the moment my section titles look like this:
SectionNumber. SectionTitle
E.g. 1. Introduction.

I want to change them to look like this:
ChapterNumber.SectionNumber. SectionTitle
E.g. 1.1. Introduction.

Is there a simple way to so ...