[R] Perpendicular symbol in plotmath?

[Matthew Neilson]

Hey,

Does anyone know of an equivalent to the LaTeX \perp (perpendicular)
symbol for adding to R plots? Parallel is easy enough ("||"), but I 
haven't been
able to find a way of adding perpendicular. The plotmath documentation
doesn't mention how to do it, so I'm inclined to think that it doesn't
exist - but surely there must be some way of achieving the desired 
result,
right?

Any help will be much appreciated,


-Matt