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Schematic representations of Frank's model (A) and the APED model (B). (A) Circled S, synthesis of chiral compounds XL and XD from achiral compounds F; circled C, autocatalysis by XL and XD; circled M, mutual destruction of XL and XD to P. (B) Circled A, activation of L and D to L* and D*; circled P, polymerization from L* and D* to Xn; circled E, epimerization between polymers; circled D, depolymerization of Xn back to L and D.
