[XeTeX] help with combining text/math

[Scott Murman]

every few months i find a spare 1/2-hour to move further in the xetex 
learning curve.  i've been able to get many of my files to process, 
though i'm still missing some functionality.  i'm still trying to 
understand the choices i have for mixing math & text.

using fontspec to change the text font also changes some of the math 
characters.   is it possible to disable this? at this point i'd be 
happy to limit myself to the regular cm math fonts, and a light-stroke 
text font.

i've seen the xeuler package, and while i had trouble getting it 
working, i'm not depressed about this since the euler fonts are 
unattractive IMO.

i notice some (many) are using the lucida math fonts.  how much are 
these?  are there any sample results around?

sorry if some of this is obvious or old news.

-SM-