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This document is a style guide. Pages are not required to follow it, but any page that does should link to this page using <code>{{<nowiki />User:Inthar/Template:Notation}}</code>. | |||
== Math notation == | == Math notation == | ||
This section documents | This section documents notation that may differ from conventional xen notation or conventional math notation. | ||
=== Variables === | === Variables === | ||
<!--* Capital italicized Latin letters may denote scales written cumulatively: i.e. with ''S''(0) = '''0''' and ''S''(''i'' + ''p'') = '''E''' + ''S''(''i'') (''p'' = length, '''E''' = equave) for every ''i''. | <!--* Capital italicized Latin letters may denote scales written cumulatively: i.e. with ''S''(0) = '''0''' and ''S''(''i'' + ''p'') = '''E''' + ''S''(''i'') (''p'' = length, '''E''' = equave) for every ''i''. | ||
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** <math>\sum_{n=a}^{b-1}s(n) = S(b)-S(a) \ \text{if} \ s(n) := S(n+1)-S(n)</math>--> | ** <math>\sum_{n=a}^{b-1}s(n) = S(b)-S(a) \ \text{if} \ s(n) := S(n+1)-S(n)</math>--> | ||
* Bolded variables denote interval sizes (especially letters of scale words) and elements of lattices. This is optional, but may be used for visual clarity, particularly in pages with more mathematical notation. '''0''' is the unison. | * Bolded variables denote interval sizes (especially letters of scale words) and elements of lattices. This is optional, but may be used for visual clarity, particularly in pages with more mathematical notation. '''0''' is the unison. | ||
** 5'''L''' 2'''s''' | ** 5'''L''' 2'''s''' | ||
* Sans serif function names are scale constructions, or more generally functions named more verbosely than is typical for conventional math notation. The page should define any sans-serif functions clearly, as it should any notation not specifically stated on this page. | * Sans serif function names are scale constructions, or more generally functions named more verbosely than is typical for conventional math notation. The page should define any sans-serif functions clearly, as it should any notation not specifically stated on this page. | ||
** Blackdye is <math>\mathsf{Flought}(\mathrm{Pyth}[5]; 10/9)</math> | ** Blackdye is <math>\mathsf{Flought}(\mathrm{Pyth}[5]; 10/9)</math> | ||
=== | === Sets === | ||
* For <math> | * For conciseness the following notation is provided for ranges. For <math>x \in \mathbb{R}</math> and <math>n\in \mathbb{Z}_{>0},</math> <math>[n]_x</math> denotes <math>\{x, x+1, ..., x+n-1\}.</math> [0]<sub>x</sub> is the empty set, and [ω]<sub>''x''</sub> is the set <math>\{x + n : n \in \mathbb{Z}_{\geq 0}\}.</math> | ||
** You may also use <math>[i:j]</math> for <math>[j-i]_i</math> and <math>[i:]</math> for <math>[\omega]_i.</math> | |||
=== Words === | === Words === | ||
* Zero-indexing is used for word indices. | * Zero-indexing is used for word indices. | ||
* A ''(linear) word'' is a function <math>w : [n]_0 \to \mathcal{A}</math> where <math>\mathcal{A}</math> is a set of letters and <math>n \in \mathbb{Z}_{\ge 0} | * A ''(linear) word'' is a function <math>w : [n]_0 \to \mathcal{A}</math> where <math>\mathcal{A}</math> is a set of letters and <math>n \in \mathbb{Z}_{\ge 0}</math> or {{nowrap|''n'' {{=}} ∞}}. ''n'' is called the ''length'' of ''w''. The letter of ''w'' at index ''i'' is denoted ''w''[''i'']. If {{nowrap|0 ≤ ''i'' < ''j'' ≤ {{!}}''w''{{!}} − 1}}, the slice notation {{nowrap|''w''[''i'':''j'']}} denotes the {{nowrap|(''j'' − ''i'')}}-letter word {{nowrap|''w''[''i'']''w''[''i'' + 1]...''w''[''j'' − 1]}}. | ||
* A ''based circular word'' is a function <math> s: \mathbb{Z}/n \to \mathcal{A},</math> where by abuse of notation, ''s''[''i''] is used for ''s''[''i'' mod ''n'']. The ''period'' of a based circular word ''s'' is the minimal <math>p, 1 \le p \le |s|,</math> such that for all ''i'', <math>s[i+p]=s[i].</math> If the period of ''s'' is equal to the length of ''s'', then ''s'' is called ''primitive''. | * A ''based circular word'' is a function <math> s: \mathbb{Z}/n \to \mathcal{A},</math> where by abuse of notation, ''s''[''i''] is used for {{nowrap|''s''[''i'' mod ''n'']}}. The ''index period'' of a based circular word ''s'' is the minimal <math>p, 1 \le p \le |s|,</math> such that for all ''i'', <math>s[i+p]=s[i].</math> If the index period of ''s'' is equal to the length of ''s'', then ''s'' is called ''primitive''. | ||
* A ''(free) circular word'' is an equivalence class of based circular words equivalent under rotation, i.e. a set of the form <math>\{x\mapsto s[x], x\mapsto s[x+1], ..., x\mapsto s[x+|s|-1] \}</math> for ''s'' a based circular word. A based circular word may be called a ''mode'' of the corresponding free circular word or a rotation of the based circular word. | * A ''(free) circular word'' is an equivalence class of based circular words equivalent under rotation, i.e. a set of the form <math>\{x\mapsto s[x], x\mapsto s[x+1], ..., x\mapsto s[x+|s|-1] \}</math> for ''s'' a based circular word. Equivalently, a free circular word is an equivalence class of linear words of the same length under conjugacy. A based circular word may be called a ''mode'' of the corresponding free circular word or a rotation of the based circular word. | ||
* The length of a linear, based circular, or free circular word ''s'' is denoted {{len|''s''}} or len(''s''). | * The length of a linear, based circular, or free circular word ''s'' is denoted {{len|''s''}} or len(''s''). | ||
* For circular words ''s'', if ''i'' | * For circular words ''s'', if {{nowrap|''i'' < ''j''}} the slice notation {{nowrap|''s''[''i'':''j'']}} denotes the {{nowrap|(''j'' − ''i'')}}-letter word {{nowrap|''s''[''i'']''s''[''i'' + 1]...''s''[''j'' − 1]}}, where all indices are taken mod {{len|''s''}}. | ||
* Shifts: If ''s'' is a circular or infinite word, then for <math>k \in \mathbb{Z}, \ \sigma^k(s) = (x \mapsto s[x+k])</math> denotes ''s'' shifted to the left by ''k'' letters. | * Shifts: If ''s'' is a circular or infinite word, then for <math>k \in \mathbb{Z}, \ \sigma^k(s) = (x \mapsto s[x+k])</math> denotes ''s'' shifted to the left by ''k'' letters. | ||
* Substitution: If ''w'' is a linear or based circular word in '''X''' and possibly other letters, and ''u'' is a based circular word, then <math>\mathsf{subst}(w, \mathbf{X}, u)</math> denotes the word ''w'' but with the ''i''th occurrence of '''X''' replaced with ''u''[''i''] (for ''i'' ≥ 0). | * Substitution: If ''w'' is a linear or based circular word in '''X''' and possibly other letters, and ''u'' is a based circular word, then <math>\mathsf{subst}(w, \mathbf{X}, u)</math> denotes the word ''w'' but with the ''i''th occurrence of '''X''' replaced with ''u''[''i''] (for {{nowrap|''i'' ≥ 0}}). | ||
=== | === Algebra === | ||
* <math>\mathrm{JI}( p_1, ..., p_r )</math> is the ''p''<sub>1</sub>.[...].''p''<sub>''r''</sub> subgroup, the subgroup of <math>(\mathbb{ | * <math>\mathrm{JI}( p_1, ..., p_r )</math> is the ''p''<sub>1</sub>.[...].''p''<sub>''r''</sub> subgroup, the subgroup of <math>(\mathbb{R}_{>0}, \cdot)</math> generated by rationals <math>p_1, ..., p_r.</math> For not-necessarily-JI generators, <math>\mathrm{Mul}(p_1, ..., p_r)</math> is used. | ||
* If ''R'' is a commutative ring with 1, <math>R^r\langle a_1, ..., a_r\rangle</math> is the rank-''r'' free ''R''-module generated by basis elements <math>a_1, ..., a_r.</math> Ordered tuples in such modules are assumed to be in the given basis. Example: <math>\mathbf{m} + 3\mathbf{s} = (0,1,3) \in \mathbb{Z}^3\langle \mathbf{L}, \mathbf{m}, \mathbf{s}\rangle</math> | * If ''R'' is a commutative ring with 1, <math>R^r\langle a_1, ..., a_r\rangle</math> is the rank-''r'' free ''R''-module generated by basis elements <math>a_1, ..., a_r.</math> Ordered tuples in such modules are assumed to be in the given basis. Example: <math>\mathbf{m} + 3\mathbf{s} = (0,1,3) \in \mathbb{Z}^3\langle \mathbf{L}, \mathbf{m}, \mathbf{s}\rangle</math> | ||
=== Miscellaneous === | === Miscellaneous === | ||
* <math>\log</math> with no subscript is base e. | * <math>\log</math> with no subscript is base ''e''. | ||
== | * Avoid <math>\mathbb{N}.</math> Use <math>\mathbb{Z}_{>0}</math> or <math>\mathbb{Z}_{\ge 0}</math> depending on which is meant. | ||
== To TeX or not to TeX? == | |||
{{todo|inline=1| expand}} | |||
[[Category:Math]] | [[Category:Math]] |