Sequence - Infinite Sequences in Theoretical Computer Science

Infinite Sequences in Theoretical Computer Science

Infinite sequences of digits (or characters) drawn from a finite alphabet are of particular interest in theoretical computer science. They are often referred to simply as sequences or streams, as opposed to finite strings. Infinite binary sequences, for instance, are infinite sequences of bits (characters drawn from the alphabet {0,1}). The set C = {0, 1}∞ of all infinite, binary sequences is sometimes called the Cantor space.

An infinite binary sequence can represent a formal language (a set of strings) by setting the n th bit of the sequence to 1 if and only if the n th string (in shortlex order) is in the language. Therefore, the study of complexity classes, which are sets of languages, may be regarded as studying sets of infinite sequences.

An infinite sequence drawn from the alphabet {0, 1, ..., b−1} may also represent a real number expressed in the base-b positional number system. This equivalence is often used to bring the techniques of real analysis to bear on complexity classes.

Read more about this topic:  Sequence

Famous quotes containing the words infinite, theoretical, computer and/or science:

    Age cannot wither her, nor custom stale
    Her infinite variety. Other women cloy
    The appetites they feed, but she makes hungry
    Where most she satisfies.
    William Shakespeare (1564–1616)

    The hypothesis I wish to advance is that ... the language of morality is in ... grave disorder.... What we possess, if this is true, are the fragments of a conceptual scheme, parts of which now lack those contexts from which their significance derived. We possess indeed simulacra of morality, we continue to use many of the key expressions. But we have—very largely if not entirely—lost our comprehension, both theoretical and practical, of morality.
    Alasdair Chalmers MacIntyre (b. 1929)

    The Buddha, the Godhead, resides quite as comfortably in the circuits of a digital computer or the gears of a cycle transmission as he does at the top of a mountain or in the petals of a flower.
    Robert M. Pirsig (b. 1928)

    As a science of the unconscious it is a therapeutic method, in the grand style, a method overarching the individual case. Call this, if you choose, a poet’s utopia.
    Thomas Mann (1875–1955)