More abstract and theoretical arguments for the plausibility of the emergence of metabolism without the presence of genes include a mathematical model introduced by PERSON@1 in the early NUMBER@1 and PERSON@2 's notion of collectively autocatalytic sets , discussed later in that decade .

PERSON@1 introduced a mathematical model in the NUMBER@1 . PERSON@2 developed the notion of autocatalytic sets , which was discussed later in that decade .
