some times when we want to introduce two or more signs on top of a letter (for example tilde and bar signs over the letter u) they are entangled to each other (especially when we convert it to PDF) which makes it hard to recognize the signs in the final PDF print. For example in the the following formula:
\tilde{\bar{u}}_i
when I convert the final output into PDF, the tilde and bar are not recognizable in the printed PDF.This is bothering me and I would appreciate any help.