The package enables left subscripts and superscripts in maths mode. The sub- and superscripts are raised for optimum fitting to the symbol indexed, in such a way that left and right sub- and superscripts are set on the same level, as appropriate.

The package provides an alternative to the use of the \sideset command in the amsmath package.

The author is Stefan Karrmann. The package is Copyright © 2008,2013 Stefan Karrmann.