In
many practical cases,
AmbientSet and
FrameSet coincide, and the Identifier is the
Identity map. The
FrameSet is defined through one of five construction types that apply
to a
Coordinator, i.e., to the source structure to be used in the construction. The
definition of a
Form looks like this:
The five construction types are labeled as follows:
It is useful to discuss these construction types and the role of the involved coordinators in some
detail and to illustrate them by musical examples. We skip the Syn-type, which stands for
“Synonymy”.10
- The coordinator of Syn-construction is a
Form, whose ambient space is the frame space
of the constructed Form. Hence Synonymy allows to rename a Form and to narrow its
AmbientSet.
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The coordinator of a Simple
Form is an arbitrary one-elemented set. Pointing at
some isolated object is the basic activity that motivates simple
Denotation. In the
pointing ontology “simple” is equivalent to “single”. Hence, the Coordinator of a
Simple
Form is the pointer . itself. The FrameSet FS(S) of any simple
Form
S is always the same, namely
= {.}, while its AmbientSet AS(S) can be
any one-elemented set. The definition a SingleTone-
Form might look like
this:
Power, Limit and Colimit are known as universal constructions in category theory. For
readers not familiar with that we recall the three strategies of knowledge management
mentioned in the first section: hermeneutics, dogma and model. A closer inspection of
the ways how to manipulate denotators following these strategies gives a suitable
heuristics for these constructions.
We start with those principles of
Denotator construction that are necessary for
hermeneutic activity. A fundamental modality to go beyond mere denotation of single
objects is called Coproduct. It is the free or “unlimited” special case of the more general
Colimit type. The hermeneutician makes use of it, when refers to
Denotators of
two or more
Forms as if they were of the same
Form. One may even build
Coproduct of multiple copies of a given
Form. This is a suitable way to define a
TwelveTone-
Form:
The FrameSet FS(TwelveTone) = {
0,...,
11} of this
Form consits of 12 copies of the
element
of AS(SingleTone) = {
}, indexed by the positions of the 12 identical
Cofactors in the Coordinator of this
Form. The structure of such Coordinators is
explained below.