[R] Descision boundary in MASS LDA

[Rob Campbell]

Hi,

Is anyone able to give me references or explain how the "decision 
boundary" is calculated by the LDA function in MASS. e.g. p 335-336 of 
MASS 4th Ed. Since it's curved I'm assuming they're doing something like 
fitting 2-D Gaussians to the groups and plotting the contour line 
describing the intersection. I'd like to understand the general ideas 
behind this as I need a short description for a paper I'm writing. It's 
biosciences so I'm after concepts rather than many equations.

Thanks!

Rob