Figure 3.

(a) A simple cycle, that can be autocatalytic if B1 ~ A and/or B2 ~ A; or non-autocatalytic if B1 !~ A !~ B2, where ~ is the equivalency relation. (b) A valid autocatalytic cycle.

Zachar and Szathmáry BMC Biology 2010 8:21   doi:10.1186/1741-7007-8-21
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