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You write that he is "trying to say that Turing did nothing new, his work is a mere extension of Godel's (!), and he only accounted for practical computational
by P-NP 5y ago
You write that he is "trying to say that Turing did nothing new, his work is a mere extension of Godel's (!), and he only accounted for practical computational reality. That is not true." However, Schmidhuber's text on Gödel/Church/Turing/Post/Zuse is much more nuanced than that:
"In 1935, Alonzo Church derived a corollary / extension of Gödel's result by showing that Hilbert & Ackermann's famous Entscheidungsproblem (decision problem) does not have a general solution.[CHU] To do this, he used his alternative universal coding language called Untyped Lambda Calculus, which forms the basis of the highly influential programming language LISP.
In 1936, Alan Turing introduced yet another universal model which has become perhaps the most well-known of them all (at least in computer science): the Turing Machine.[TUR] He rederived the above-mentioned result.[T20](Sec. IV) Of course, he cited both Gödel and Church in his 1936 paper[TUR] (whose corrections appeared in 1937). In the same year of 1936, Emil Post published yet another independent universal model of computing,[POS] also citing Gödel and Church. Today we know many such models. Nevertheless, according to Wang,[WA74-96] it was Turing's work (1936) that convinced Gödel of the universality of both his own approach (1931-34) and Church's (1935).
What exactly did Post[POS] and Turing[TUR] do in 1936 that hadn't been done earlier by Gödel[GOD][GOD34] (1931-34) and Church[CHU] (1935)? There is a seemingly minor difference whose significance emerged only later. Many of Gödel's instruction sequences were series of multiplications of number-coded storage contents by integers. Gödel did not care that the computational complexity of such multiplications tends to increase with storage size. Similarly, Church also ignored the spatio-temporal complexity of the basic instructions in his algorithms. Turing and Post, however, adopted a traditional, reductionist, minimalist, binary view of computing—just like Konrad Zuse (1936).[ZU36] Their machine models permitted only very simple elementary instructions with constant complexity, like the early binary machine model of Leibniz (1679).[L79][LA14][HO66] They did not exploit this back then—for example, in 1936, Turing used his (quite inefficient) model only to rephrase the results of Gödel and Church on the limits of computability. Later, however, the simplicity of these machines made them a convenient tool for theoretical studies of complexity. (I also happily used and generalized them for the case of never-ending computations.[ALL2])"
- P-NP 5y agoYou also write that Turing's work "paved the way for modern general computers." According to the text, however, this practical part really started with Konrad Zuse's patent application of 1936: "The formal models of Gödel (1931-34), Church (1935), Turing (1936), and Post (1936) were theoretical pen & paper constructs that cannot directly serve as a foundation for practical computers. Remarkably, Konrad Zuse's patent application[ZU36-38][Z36][RO98] for the first practical general-purpose program-controlled computer also dates back to 1936. It describes general digital circuits (and predates Claude Shannon's 1937 thesis on digital circuit design[SHA37]). Then, in 1941, Zuse completed Z3, the world's first practical, working, programmable computer (based on the 1936 application). Ignoring the inevitable storage limitations of any physical computer, the physical hardware of Z3 was indeed universal in the "modern" sense of Gödel, Church, Turing, and Post—simple arithmetic tricks can compensate for Z3's lack of an explicit conditional jump instruction.[RO98]"
- truth_ 5y ago> According to the text, however, this practical part really started with Konrad Zuse's patent application of 1936 "According to the text" I don't agree with the text, that is the point.
- P-NP 5y agoSo you don't agree with the text but can you point out a concrete error instead of referring to "Many of the child parents to my main address to that"? I could not really find anything convincing in those child parents.