The \intertext command in the amsmath package for LaTeX is useful for interjecting text between two aligned rows of displayed math. However, it puts too much space around the text: compared to the usual vertical spacing around displayed math, it leaves \jot too much, both above and below. (\jot is 3 pt or more.) To fix this problem, load my amsmath1 package with the intertext option.

While investigating this problem, Dylan and I discovered the mathtools and nccmath packages, which add many useful macros to amsmath. Unfortunately, even though both packages extend \intertext, neither package really removes the extra \jot space.