How would you write the model?

Suppose you have SAS code as follows. This is from http://www.ats.ucla.edu/stat/sas/faq/anovmix1.htm.

 PROC MIXED DATA=long;
CLASS sub group trial;
MODEL dv = group trial group*trial;
REPEATED trial / SUBJECT=sub TYPE=CS;
run;


How would you write the model for this? Would it be:

dv = group + trial +group*trial + subj + error? I am a little confused about how to write the mixed model in terms of a mathematical equation.

$Y = X\beta + z\gamma + \epsilon$