macro location for \bf in math mode (Chapter 13)

[T. Alderson]

Hi,

Can anyone point me to the location (in the source) of the macro that is meant to make \bf work in math mode?

I'm having a problem producing the text whereby the \bf commands (in Section 13.2 for example) are not working. ${\bf r}$ produces \  and ${\bf s}$ produces ~.

Thanks,

Tim.       

[T. Alderson]

I found the culprit..My version called on the mathptmx package.  Removing this line resolved the problem.