# Use of ~ (\tilde) on the top of Capital letters

For small letters a,b,c,d, we can put ~ on the top of these letters by

\tilde{a}, \tilde{b}, \tilde{c}, etc.


and they are clearly visible in the output. But, while putting them on Capital letters A,B,C,D, it is not so clearly visible in the output, i.e. by the commands

\tilde{A}, \tilde{B}, \tilde{C}, etc.


the symbol ~ on the top of these letters appears to be small compared to them. How can we enlarge it? or is there any other way to put sufficiently large ~ on the top of the Capital letters?

• Apr 2, 2016 at 11:12

Type \widetilde{A}, \widetilde{B}, \widetilde{C}, etc. to get wider tilde symbols.

• Incidentally, \widetilde is available in both in LaTeX and PlainTeX.
– Mico
Apr 2, 2016 at 7:15
• Unfortunately, \widetilde{X} does not look nice to me. The tilde is very wide, and it also does not appear to be centered well. Currently looking for a nice alternative... May 5, 2020 at 11:11
• @jhin - Speaking for myself here (obviously): I think the main problem is not with the \widetilde{X} but wih the use of ^T to denote (matrix) transposes. I'd use either ' ("prime") or a dedicated macro called, say, \transp (see, e.g., the definition below). \documentclass{article} \usepackage{stix2} \newcommand\transp{^{\scriptscriptstyle\top}\!} \begin{document} $\displaystyle (\widetilde{X}^T\widetilde{X})^{-1}\widetilde{X}^Ty \quad (\widetilde{X}\transp\widetilde{X})^{-1}\widetilde{X}\transp y \quad (\widetilde{X}'\widetilde{X})^{-1}\widetilde{X}'y$ \end{document}
• @jhin - For more information on the subject of transpose operators in a Latex document, please see What is the best symbol for vector/matrix transpose? Clearly, there is no consensus on what might be the "best" symbol. My recommendation: Make an informed choice and stick with it. :-) By the way, if you define \transp as a macro, you give yourself an easy path toward changing the appearance of the transpose operator should you ever feel a need to do so.