undertilde-gen – A simple macro for placing a tilde under a character
The code creates a \mathord at standard size (no attempt to adjust for different contexts in a mathematical expression).
Benjamin Bayart's undertilde (for all its faults) does the job better—the general user could easily remove the LaTeX mechanisms from the file.
|MiKTeX as genmisc
Maybe you are interested in the following packages as well.
- kbordermatrix: LaTeX version of \bordermatrix
- tabto-generic: "Tab" to a measured position in the line
- backgrnd: Mark text with grey background or change bar
- chessmin: Minimal chess diagrams