fmtlatex.spad line 100 [edit on github]
FormatLaTeX provides a coercion from OutputForm to LaTeX format. The particular dialect of TeX used is LaTeX, but for flexibility reasons FormatLaTeX outputs everything into a fricasmath environment in which certain additional commands are available. These commands are defined in a .sty file that is distributed with the source code of FriCAS.
environmnt(env, x, sep) returns a handler that typesets its arguments (without parentheses) in a LaTeX environment with name env. The string x is put right after the start of the environment. The arguments are separated by the string sep.