• Equation, which is the standard equation environment, with an optional argument for a label name;
• Multiline, which is broadly similar to the amsmath multline environment, creating a pleasing layout for equations that run over several lines;
• System, for grouping a set of equations together within a left brace, with only one equation number; and
• EqSystem, similar to System, except that each equation has its own number.

The author is Francesco Bosisio. The package is Copyright © 1997-2010 F. Bosisio.