I'm seeing various things fail when I try to next braces inside \eqn. This source \eqn{{\bf\beta}_j}{b(j)} is the vector produces this error ---------------------------------------------- [4] ! Missing $ inserted. <inserted text> $ l.258 \eqn{{\bf\beta}_j}{\bf\beta}_ j{{b(j)} is the vector of coefficients fo... I've inserted a begin-math/end-math symbol since I think you left one out. Proceed, with fingers crossed. ! Missing } inserted. <inserted text> } l.258 ...tor of coefficients for outcome \eqn{j}{} and I've inserted something that you may have forgotten. ------------------------------------------------------- Notice that the argument seems to have been doubled. I tried using \begingroup and \endgroup, and ran into problem with a later \eqn with nested braces. For reference, particularly in case I've missed something earlier, here is a fuller excerpt from the input file: -------------------------------------------- With \eqn{J} possible outcomes and \eqn{p_j}{p(j)} the probability of the \eqn{j}'th outcome, the formula is \deqn{\newcommand{\B}{{\bf \beta}}\newcommand{\X}{{\bf X}} p_j = \frac{e^{\X\B_j}}{\displaystyle\sum_{k=0}^J e^{\X\B_k}}.}{ p(j) = exp[X*b(j)]/sum{exp[X*b(k)], k=0 to J}.} \eqn{{\bf\beta}_j}{b(j)} is the vector of coefficients for outcome \eqn{j} and \eqn{{\bf X}}{X} are the covariates. -------------------------------------------- By the way, the \newcommand is not global, so I can't use \B (for example) in later \eqn's. Using R 2.0.0. -- Ross Boylan wk: (415) 502-4031 530 Parnassus Avenue (Library) rm 115-4 ross at biostat.ucsf.edu Dept of Epidemiology and Biostatistics fax: (415) 476-9856 University of California, San Francisco San Francisco, CA 94143-0840 hm: (415) 550-1062