History Monoid - Product Monoids and Projection

Product Monoids and Projection

Let

denote an n-tuple of alphabets . Let denote all possible combinations of finite-length strings from the alphabets:

(In more formal language, is the Cartesian product of the free monoids of the . The superscript star is the Kleene star.) Composition in the product monoid is component-wise, so that, for

and

then

for all in . Define the union alphabet to be

(The union here is the set union, not the disjoint union.) Given any string, we can pick out just the letters in some using the corresponding string projection . A distribution is the mapping that operates on with all of the, separating it into components in each free monoid:

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Famous quotes containing the words product and/or projection:

    The history is always the same the product is always different and the history interests more than the product. More, that is, more. Yes. But if the product was not different the history which is the same would not be more interesting.
    Gertrude Stein (1874–1946)

    Those who speak of our culture as dead or dying have a quarrel with life, and I think they cannot understand its terms, but must endlessly repeat the projection of their own desires.
    Muriel Rukeyser (1913–1980)