On 4/11/2011 4:36 AM, rusi wrote:
http://www.cse.uconn.edu/~dqg/papers/cie05.pdf
may be of interest (and also other papers of Peter Wegner questioning
the universality of Turing machines lambda calculus etc)
Thank you for that reference. In summary, it says that while Turing
machine are universal for finite function calculations, infinite
interactive processes are not (finite) function calculations, and
therefore need an extension to TMs. This is pretty obviously correct.
Python iterators, and especially generators, implement the extension
that the authors call 'persistent Turing machines' (PTMs, section 6.2),
except that iterators (and generators by default) operate in 'pull'
mode, while they describe PTMs as operating in 'push' mode (as with
generator.send()).
--
Terry Jan Reedy
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