Information Technology Reference
In-Depth Information
Fig. 7.19
A 4-coloration
Fig. 7.20
A planar representation of an icosahedron
consists of words which determine its meaning, but conversely the semantic function
of a word is determined by the class of texts where it occurs. More technical exam-
ples of duality can be found in linear algebra (vectors and linear transformations)
and in geometry (points and lines), but cases of duality can be found in biochemistry
between metabolic states and reactions (both representable as suitable vectors), or
in cell biology where genes and proteins can be considered as dual entities playing
the roles of informational and functional biomolecules. The common aspect of all
forms of duality is the intrinsic necessity of concepts which are paired, and which
can be fully described and analyzed only when they are related, because each of
them postulates the other one in order to be completely defined, as it happens in the
bilateral symmetry of organisms or in the double-stranded DNA molecules.
