Applying the same procedure to any positive integer <math>n\!</math> produces an expression called the ''doubly recursive factorization'' (DRF) of <math>n.\!</math> This corresponding function from positive integers to DRF expressions may be indicated as <math>\operatorname{drf}(n).\!</math>
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Applying the same procedure to any positive integer <math>n\!</math> produces an expression called the ''doubly recursive factorization'' (DRF) of <math>n.\!</math> The corresponding function from positive integers to DRF expressions may be indicated as <math>\operatorname{drf}(n).\!</math>
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The form of a DRF expression can be mapped into either one of two classes of graph-theoretical structures, called riffs and ''rotes'', respectively.
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The form of a DRF expression can be mapped into either one of two classes of graph-theoretical structures, called ''riffs'' and ''rotes'', respectively.