VMS Help CMS, DELETE, GENERATION, Qualifiers, /AFTER[=generation-expression]  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Specifies the start of a range of generations that are to be
    deleted, excluding the specified generation. You cannot specify
    both /AFTER and /FROM or both /AFTER and /GENERATION. You must
    specify the end of the range with either the /BEFORE or /TO
    qualifier.