Notation

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aX	The Alexandrov compactification of X
A	An alphabet
A*	The free semigroup of all finitary strings over A
bX	The Stone-Cech compactification of X
F	A finite state recogniser
\|F\|	The (regular) language recognised by F
F^L	The X-machine with finite state core F and labelling L
L	A language
L^L	The relation computed by the (regular) language L via the labelling L
L	A labelling, i.e., a function L: A `---->` Rel_X
\|L\|	The subset of Rel_X computed by L
M	An X-machine
M₀	The finite state core of M
\|M\|	The relation computed by M
Rel_X	The semigroup 2^X×X of all relations on X
X	The fundamental datatype