Fokker block: Difference between revisions
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{{Inaccessible}} <!-- add beginner section that explains how to build Fokker blocks either by hand or using common software, along with visualizations? --> | {{Inaccessible}} <!-- add beginner section that explains how to build Fokker blocks either by hand or using common software, along with visualizations? --> | ||
{{Wikipedia| Fokker periodicity block }} | {{Wikipedia| Fokker periodicity block }} | ||
A '''Fokker block''' (an invention of physicist and music theorist [[Adriaan Fokker]]) is a [[Constant structure|constant-structure]] scale comprising elements of the [[lattice]] of pitch classes which fall inside or on the boundary of a [[wikipedia:Parallelepiped#Parallelotope|parellelotope]], the edges of which correspond to small intervals called ''' | A '''Fokker block''' (an invention of physicist and music theorist [[Adriaan Fokker]]) is a [[Constant structure|constant-structure]] scale comprising elements of the [[lattice]] of pitch classes which fall inside or on the boundary of a [[wikipedia:Parallelepiped#Parallelotope|parellelotope]], the edges of which correspond to small intervals called '''chromas''' (singular '''chroma'''). The scale repeats at the [[interval of equivalence]], and the interval of equivalence does not lie on the lattice (as it is a lattice of pitch classes). The rank of a Fokker block is the rank of the underlying lattice of pitches including the interval of equivalence. | ||
A Fokker block of rank r has [[maximum variety]] at most 2(r − 1). For example, a rank-2 Fokker block has max variety at most 2 (hence is a [[MOS scale|mos]]), and a rank-3 Fokker block has max variety at most 4. In this way, Fokker blocks generalize mosses. | A Fokker block of rank r has [[maximum variety]] at most 2(r − 1). For example, a rank-2 Fokker block has max variety at most 2 (hence is a [[MOS scale|mos]]), and a rank-3 Fokker block has max variety at most 4. In this way, Fokker blocks generalize mosses. | ||
If the | If the chromas of a Fokker block are too large, the result will not be CS; it is then called a weak Fokker block. | ||
== Mathematical description == | == Mathematical description == |