[R] notation question

[Carson Farmer]

Dear list, I am currently writing up some of my R models in a more
formal sense for a paper, and I am having trouble with the notation.
Although this isn't really an 'R' question, it should help me to
understand a bit better what I am actually doing when fitting my
models!

Using the analysis of co-variance example from MASS (fourth edition, p
142), what is the correct notation for the formula "Gas, ~ Insul/Temp
- 1"? Obviously, if we fit it as two separate models (as in the
example above it), we would have something like y_i = \beta x_i for
each of the two models. So my question is, when we have a single model
with a k-level factor interaction term as in the equation above, what
is the correct/standard statistical (LaTeX style) notation?

Cheers,

Carson