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| {{DISPLAYTITLE:Riffs and Rotes}} | | {{DISPLAYTITLE:Riffs and Rotes}} |
− | __TOC__ | + | <div class="nonumtoc">__TOC__</div> |
| | | |
| ==Idea== | | ==Idea== |
| | | |
− | Let <math>\text{p}_i</math> be the <math>i^\text{th}</math> prime, where the positive integer <math>i</math> is called the ''index'' of the prime <math>\text{p}_i</math> and the indices are taken in such a way that <math>\text{p}_1 = 2.</math> Thus the sequence of primes begins as follows: | + | Let <math>\text{p}_i\!</math> be the <math>i^\text{th}\!</math> prime, where the positive integer <math>i\!</math> is called the ''index'' of the prime <math>\text{p}_i\!</math> and the indices are taken in such a way that <math>\text{p}_1 = 2.\!</math> Thus the sequence of primes begins as follows: |
| | | |
| {| align="center" cellpadding="6" width="90%" | | {| align="center" cellpadding="6" width="90%" |
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| |} | | |} |
| | | |
− | The prime factorization of a positive integer <math>n</math> can be written in the following form: | + | The prime factorization of a positive integer <math>n\!</math> can be written in the following form: |
| | | |
| {| align="center" cellpadding="6" width="90%" | | {| align="center" cellpadding="6" width="90%" |
− | | <math>n ~=~ \prod_{k = 1}^{\ell} \text{p}_{i(k)}^{j(k)},</math> | + | | <math>n ~=~ \prod_{k = 1}^{\ell} \text{p}_{i(k)}^{j(k)},\!</math> |
| |} | | |} |
| | | |
− | where <math>\text{p}_{i(k)}^{j(k)}</math> is the <math>k^\text{th}</math> prime power in the factorization and <math>\ell</math> is the number of distinct prime factors dividing <math>n.</math> The factorization of <math>1</math> is defined as <math>1</math> in accord with the convention that an empty product is equal to <math>1.</math> | + | where <math>\text{p}_{i(k)}^{j(k)}\!</math> is the <math>k^\text{th}\!</math> prime power in the factorization and <math>\ell\!</math> is the number of distinct prime factors dividing <math>n.\!</math> The factorization of <math>1\!</math> is defined as <math>1\!</math> in accord with the convention that an empty product is equal to <math>1.\!</math> |
| | | |
− | Let <math>I(n)</math> be the set of indices of primes that divide <math>n</math> and let <math>j(i, n)</math> be the number of times that <math>\text{p}_i</math> divides <math>n.</math> Then the prime factorization of <math>n</math> can be written in the following alternative form: | + | Let <math>I(n)\!</math> be the set of indices of primes that divide <math>n\!</math> and let <math>j(i, n)\!</math> be the number of times that <math>\text{p}_i\!</math> divides <math>n.\!</math> Then the prime factorization of <math>n\!</math> can be written in the following alternative form: |
| | | |
| {| align="center" cellpadding="6" width="90%" | | {| align="center" cellpadding="6" width="90%" |
− | | <math>n ~=~ \prod_{i \in I(n)} \text{p}_{i}^{j(i, n)}.</math> | + | | <math>n ~=~ \prod_{i \in I(n)} \text{p}_{i}^{j(i, n)}.\!</math> |
| |} | | |} |
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| | | | | |
| <math>\begin{matrix} | | <math>\begin{matrix} |
− | 9876543210
| + | 123456789 |
− | & = & 2 \cdot 3^2 \cdot 5 \cdot {17}^2 \cdot 379721 | + | & = & 3^2 \cdot 3607 \cdot 3803 |
− | & = & \text{p}_1^1 \text{p}_2^2 \text{p}_3^1 \text{p}_7^2 \text{p}_{32277}^1. | + | & = & \text{p}_2^2 \text{p}_{504}^1 \text{p}_{529}^1. |
| \end{matrix}</math> | | \end{matrix}</math> |
| |} | | |} |
| | | |
− | Each index <math>i</math> and exponent <math>j</math> appearing in the prime factorization of a positive integer <math>n</math> is itself a positive integer, and thus has a prime factorization of its own. | + | Each index <math>i\!</math> and exponent <math>j\!</math> appearing in the prime factorization of a positive integer <math>n\!</math> is itself a positive integer, and thus has a prime factorization of its own. |
| | | |
− | Continuing with the same example, the index <math>32277</math> has the factorization <math>3 \cdot 7 \cdot 29 \cdot 53 = \text{p}_2^1 \text{p}_4^1 \text{p}_{10}^1 \text{p}_{16}^1.</math> Taking this information together with previously known factorizations allows the following replacements to be made: | + | Continuing with the same example, the index <math>504\!</math> has the factorization <math>2^3 \cdot 3^2 \cdot 7 = \text{p}_1^3 \text{p}_2^2 \text{p}_4^1\!</math> and the index <math>529\!</math> has the factorization <math>{23}^2 = \text{p}_9^2.\!</math> Taking this information together with previously known factorizations allows the following replacements to be made in the expression above: |
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| {| align="center" cellpadding="6" width="90%" | | {| align="center" cellpadding="6" width="90%" |
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| 2 & \mapsto & \text{p}_1^1 | | 2 & \mapsto & \text{p}_1^1 |
| \\[6pt] | | \\[6pt] |
− | 3 & \mapsto & \text{p}_2^1
| + | 504 & \mapsto & \text{p}_1^3 \text{p}_2^2 \text{p}_4^1 |
| \\[6pt] | | \\[6pt] |
− | 7 & \mapsto & \text{p}_4^1
| + | 529 & \mapsto & \text{p}_9^2 |
− | \\[6pt]
| |
− | 32277 & \mapsto & \text{p}_2^1 \text{p}_4^1 \text{p}_{10}^1 \text{p}_{16}^1
| |
| \end{array}</math> | | \end{array}</math> |
| |} | | |} |
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| | | | | |
| <math>\begin{array}{lll} | | <math>\begin{array}{lll} |
− | 9876543210
| + | 123456789 |
− | & = & \text{p}_1^1 \text{p}_2^2 \text{p}_3^1 \text{p}_7^2 \text{p}_{32277}^1 | + | & = & \text{p}_2^2 \text{p}_{504}^1 \text{p}_{529}^1 |
| \\[12pt] | | \\[12pt] |
− | & = & \text{p}_1^1 \text{p}_{\text{p}_1^1}^{\text{p}_1^1} \text{p}_{\text{p}_2^1}^1 \text{p}_{\text{p}_4^1}^{\text{p}_1^1} \text{p}_{\text{p}_2^1 \text{p}_4^1 \text{p}_{10}^1 \text{p}_{16}^1}^1 | + | & = & \text{p}_{\text{p}_1^1}^{\text{p}_1^1} \text{p}_{\text{p}_1^3 \text{p}_2^2 \text{p}_4^1}^1 \text{p}_{\text{p}_9^2}^1 |
| \end{array}</math> | | \end{array}</math> |
| |} | | |} |
| | | |
− | Continuing to replace every index and exponent with its factorization until no indices or exponents greater than <math>1</math> are left produces the following developemnt: | + | Continuing to replace every index and exponent with its factorization produces the following development: |
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| {| align="center" cellpadding="6" width="90%" | | {| align="center" cellpadding="6" width="90%" |
| | | | | |
| <math>\begin{array}{lll} | | <math>\begin{array}{lll} |
− | 9876543210
| + | 123456789 |
− | & = & \text{p}_1^1 \text{p}_2^2 \text{p}_3^1 \text{p}_7^2 \text{p}_{32277}^1 | + | & = & \text{p}_2^2 \text{p}_{504}^1 \text{p}_{529}^1 |
| \\[18pt] | | \\[18pt] |
− | & = & \text{p}_1^1 \text{p}_{\text{p}_1^1}^{\text{p}_1^1} \text{p}_{\text{p}_2^1}^1 \text{p}_{\text{p}_4^1}^{\text{p}_1^1} \text{p}_{\text{p}_2^1 \text{p}_4^1 \text{p}_{10}^1 \text{p}_{16}^1}^1 | + | & = & \text{p}_{\text{p}_1^1}^{\text{p}_1^1} \text{p}_{\text{p}_1^3 \text{p}_2^2 \text{p}_4^1}^1 \text{p}_{\text{p}_9^2}^1 |
| \\[18pt] | | \\[18pt] |
− | & = & \text{p}_1^1 \text{p}_{\text{p}_1^1}^{\text{p}_1^1} \text{p}_{\text{p}_{\text{p}_1^1}^1}^1 \text{p}_{\text{p}_{\text{p}_1^2}^1}^{\text{p}_1^1} \text{p}_{\text{p}_{\text{p}_1^1}^1 \text{p}_{\text{p}_1^2}^1 \text{p}_{\text{p}_1^1 \text{p}_3^1}^1 \text{p}_{\text{p}_1^4}^1}^1 | + | & = & \text{p}_{\text{p}_1^1}^{\text{p}_1^1} \text{p}_{\text{p}_1^{\text{p}_2^1} \text{p}_{\text{p}_1^1}^{\text{p}_1^1} \text{p}_{\text{p}_1^2}^1}^1 \text{p}_{\text{p}_{\text{p}_2^2}^{\text{p}_1^1}}^1 |
| \\[18pt] | | \\[18pt] |
− | & = & \text{p}_1^1 \text{p}_{\text{p}_1^1}^{\text{p}_1^1} \text{p}_{\text{p}_{\text{p}_1^1}^1}^1 \text{p}_{\text{p}_{\text{p}_1^{\text{p}_1^1}}^1}^{\text{p}_1^1} \text{p}_{\text{p}_{\text{p}_1^1}^1 \text{p}_{\text{p}_1^{\text{p}_1^1}}^1 \text{p}_{\text{p}_1^1 \text{p}_{\text{p}_2^1}^1}^1 \text{p}_{\text{p}_1^{\text{p}_1^2}}^1}^1 | + | & = & \text{p}_{\text{p}_1^1}^{\text{p}_1^1} \text{p}_{\text{p}_1^{\text{p}_{\text{p}_1^1}^1} \text{p}_{\text{p}_1^1}^{\text{p}_1^1} \text{p}_{\text{p}_1^{\text{p}_1^1}}^1}^1 \text{p}_{\text{p}_{\text{p}_{\text{p}_1^1}^{\text{p}_1^1}}^{\text{p}_1^1}}^1 |
− | \\[18pt]
| + | \end{array}</math> |
− | & = & \text{p}_1^1 \text{p}_{\text{p}_1^1}^{\text{p}_1^1} \text{p}_{\text{p}_{\text{p}_1^1}^1}^1 \text{p}_{\text{p}_{\text{p}_1^{\text{p}_1^1}}^1}^{\text{p}_1^1} \text{p}_{\text{p}_{\text{p}_1^1}^1 \text{p}_{\text{p}_1^{\text{p}_1^1}}^1 \text{p}_{\text{p}_1^1 \text{p}_{\text{p}_{\text{p}_1^1}^1}^1}^1 \text{p}_{\text{p}_1^{\text{p}_1^{\text{p}_1^1}}}^1}^1
| + | |} |
| + | |
| + | The <math>1\!</math>'s that appear as indices and exponents are formally redundant, conveying no information apart from the places they occupy in the resulting syntactic structure. Leaving them tacit produces the following expression: |
| + | |
| + | {| align="center" cellpadding="6" width="90%" |
| + | | |
| + | <math>\begin{array}{lll} |
| + | 123456789 |
| + | & = & \text{p}_{\text{p}}^{\text{p}} \text{p}_{\text{p}^{\text{p}_{\text{p}}} \text{p}_{\text{p}}^{\text{p}} \text{p}_{\text{p}^{\text{p}}}} \text{p}_{\text{p}_{\text{p}_{\text{p}}^{\text{p}}}^{\text{p}}} |
| \end{array}</math> | | \end{array}</math> |
| + | |} |
| + | |
| + | The pattern of indices and exponents illustrated here is called a ''doubly recursive factorization'', or ''DRF''. Applying the same procedure to any positive integer <math>n\!</math> produces an expression called the DRF of <math>n.\!</math> If <math>\mathbb{M}</math> is the set of positive integers, <math>\mathcal{L}</math> is the set of DRF expressions, and the mapping defined by the factorization process is denoted <math>\operatorname{drf} : \mathbb{M} \to \mathcal{L},</math> then the doubly recursive factorization of <math>n\!</math> is denoted <math>\operatorname{drf}(n).\!</math> |
| + | |
| + | The forms of DRF expressions can be mapped into either one of two classes of graph-theoretical structures, called ''riffs'' and ''rotes'', respectively. |
| + | |
| + | {| align=center cellpadding="6" width="90%" |
| + | |- |
| + | | <math>\operatorname{riff}(123456789)</math> is the following digraph: |
| + | |- |
| + | | align=center | [[Image:Riff 123456789 Big.jpg|220px]] |
| + | |- |
| + | | <math>\operatorname{rote}(123456789)</math> is the following graph: |
| + | |- |
| + | | align=center | [[Image:Rote 123456789 Big.jpg|345px]] |
| |} | | |} |
| | | |
| ==Riffs in Numerical Order== | | ==Riffs in Numerical Order== |
| | | |
− | {| align="center" border="1" cellpadding="10" | + | {| align="center" border="1" cellpadding="12" |
| |+ style="height:25px" | <math>\text{Riffs in Numerical Order}\!</math> | | |+ style="height:25px" | <math>\text{Riffs in Numerical Order}\!</math> |
| | valign="bottom" | | | | valign="bottom" | |
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| {| align="center" border="1" cellpadding="6" | | {| align="center" border="1" cellpadding="6" |
| + | |+ style="height:25px" | <math>\text{Rotes in Numerical Order}\!</math> |
| | valign="bottom" | | | | valign="bottom" | |
| <p>[[Image:Rote 1 Big.jpg|20px]]</p><br> | | <p>[[Image:Rote 1 Big.jpg|20px]]</p><br> |
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| <p><math>\text{p}^\text{p} \text{p}_\text{p} \text{p}_{\text{p}_\text{p}}\!</math></p><br> | | <p><math>\text{p}^\text{p} \text{p}_\text{p} \text{p}_{\text{p}_\text{p}}\!</math></p><br> |
| <p><math>\begin{array}{l} 1\!:\!2 ~~ 2\!:\!1 ~~ 3\!:\!1 \\ 60 \end{array}</math></p> | | <p><math>\begin{array}{l} 1\!:\!2 ~~ 2\!:\!1 ~~ 3\!:\!1 \\ 60 \end{array}</math></p> |
| + | |} |
| + | |
| + | ==Prime Animations== |
| + | |
| + | ===Riffs 1 to 60=== |
| + | |
| + | {| align="center" |
| + | | [[Image:Animation Riff 60 x 0.16.gif]] |
| + | |} |
| + | |
| + | ===Rotes 1 to 60=== |
| + | |
| + | {| align="center" |
| + | | [[Image:Animation Rote 60 x 0.16.gif]] |
| |} | | |} |
| | | |
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| * '''Number of "rooted odd trees with only exponent symmetries" (Rotes) on 2n+1 nodes.''' | | * '''Number of "rooted odd trees with only exponent symmetries" (Rotes) on 2n+1 nodes.''' |
| | | |
− | * [http://oeis.org/wiki/A061396 OEIS Wiki Entry for A061396]. | + | * [http://oeis.org/A061396 OEIS Entry for A061396]. |
| | | |
| {| align="center" border="1" width="96%" | | {| align="center" border="1" width="96%" |
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| * '''Triangle in which k-th row lists natural number values for the collection of riffs with k nodes.''' | | * '''Triangle in which k-th row lists natural number values for the collection of riffs with k nodes.''' |
| | | |
− | * [http://oeis.org/wiki/A062504 OEIS Wiki Entry for A062504]. | + | * [http://oeis.org/A062504 OEIS Entry for A062504]. |
| | | |
| {| align="center" | | {| align="center" |
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| * '''Nodes in riff (rooted index-functional forest) for n.''' | | * '''Nodes in riff (rooted index-functional forest) for n.''' |
| | | |
− | * [http://oeis.org/wiki/A062537 OEIS Wiki Entry for A062537]. | + | * [http://oeis.org/A062537 OEIS Entry for A062537]. |
| | | |
| {| align="center" border="1" cellpadding="10" | | {| align="center" border="1" cellpadding="10" |
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| * '''Smallest j with n nodes in its riff (rooted index-functional forest).''' | | * '''Smallest j with n nodes in its riff (rooted index-functional forest).''' |
| | | |
− | * [http://oeis.org/wiki/A062860 OEIS Wiki Entry for A062860]. | + | * [http://oeis.org/A062860 OEIS Entry for A062860]. |
| | | |
| {| align="center" border="1" cellpadding="10" | | {| align="center" border="1" cellpadding="10" |
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| * '''a(n) = rhig(n) = rote height in gammas of n, where the "rote" corresponding to a positive integer n is a graph derived from the primes factorization of n, as illustrated in the comments.''' | | * '''a(n) = rhig(n) = rote height in gammas of n, where the "rote" corresponding to a positive integer n is a graph derived from the primes factorization of n, as illustrated in the comments.''' |
| | | |
− | * [http://oeis.org/wiki/A109301 OEIS Wiki Entry for A109301]. | + | * [http://oeis.org/A109301 OEIS Entry for A109301]. |
| | | |
| ; Example | | ; Example |
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| <p><math>\text{p}^\text{p} \text{p}_\text{p} \text{p}_{\text{p}_\text{p}}\!</math></p><br> | | <p><math>\text{p}^\text{p} \text{p}_\text{p} \text{p}_{\text{p}_\text{p}}\!</math></p><br> |
| <p><math>a(60) ~=~ 3</math></p> | | <p><math>a(60) ~=~ 3</math></p> |
| + | |} |
| + | |
| + | ==Miscellaneous Examples== |
| + | |
| + | {| align="center" border="1" width="96%" |
| + | |+ style="height:24px" | <math>\text{Integers, Riffs, Rotes}\!</math> |
| + | |- style="height:50px; background:#f0f0ff" |
| + | | |
| + | {| cellpadding="12" style="background:#f0f0ff; text-align:center; width:100%" |
| + | | width="10%" | <math>\text{Integer}\!</math> |
| + | | width="45%" | <math>\text{Riff}\!</math> |
| + | | width="45%" | <math>\text{Rote}\!</math> |
| + | |} |
| + | |- |
| + | | |
| + | {| cellpadding="12" style="text-align:center; width:100%" |
| + | | width="10%" | <math>1\!</math> |
| + | | width="45%" | |
| + | | width="45%" | [[Image:Rote 1 Big.jpg|15px]] |
| + | |- |
| + | | <math>2\!</math> |
| + | | [[Image:Riff 2 Big.jpg|15px]] |
| + | | [[Image:Rote 2 Big.jpg|30px]] |
| + | |- |
| + | | <math>3\!</math> |
| + | | [[Image:Riff 3 Big.jpg|30px]] |
| + | | [[Image:Rote 3 Big.jpg|30px]] |
| + | |- |
| + | | <math>4\!</math> |
| + | | [[Image:Riff 4 Big.jpg|30px]] |
| + | | [[Image:Rote 4 Big.jpg|48px]] |
| + | |- |
| + | | <math>360\!</math> |
| + | | [[Image:Riff 360 Big.jpg|120px]] |
| + | | [[Image:Rote 360 Big.jpg|135px]] |
| + | |- |
| + | | <math>2010\!</math> |
| + | | [[Image:Riff 2010 Big.jpg|138px]] |
| + | | [[Image:Rote 2010 Big.jpg|144px]] |
| + | |- |
| + | | <math>2011\!</math> |
| + | | [[Image:Riff 2011 Big.jpg|84px]] |
| + | | [[Image:Rote 2011 Big.jpg|120px]] |
| + | |- |
| + | | <math>2012\!</math> |
| + | | [[Image:Riff 2012 Big.jpg|100px]] |
| + | | [[Image:Rote 2012 Big.jpg|125px]] |
| + | |- |
| + | | <math>2500\!</math> |
| + | | [[Image:Riff 2500 Big.jpg|66px]] |
| + | | [[Image:Rote 2500 Big.jpg|125px]] |
| + | |- |
| + | | <math>802701\!</math> |
| + | | [[Image:Riff 802701 Big.jpg|156px]] |
| + | | [[Image:Rote 802701 Big.jpg|245px]] |
| + | |- |
| + | | <math>123456789\!</math> |
| + | | [[Image:Riff 123456789 Big.jpg|162px]] |
| + | | [[Image:Rote 123456789 Big.jpg|256px]] |
| + | |} |
| |} | | |} |