diaries

An analogy between computer programs and mathematical proofs

Dated: 

November 1981

In 1961, Dijkstra made an analogy between mathematical proofs and computer programs. After noting the analogy, he took aspects from the field of mathematics and projected them onto his own profession of programming.

Twenty years later, Dijkstra still stood by the analogy. This time, however, he projected the lessons he had learned from programming methodology back onto mathematics. Dijkstra was thus, in 1981, keen on defining a mathematical methodology. In Dijkstra's words:

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Trip to Amsterdam, October 1981

Dated: 

26-29 October 1981

Dijkstra attended the four-day “International Symposium on Algorithmic Languages” in honor of Aad van Wijngaarden who was retiring as director of Amsterdam's `Mathematical Centre'. The symposium was held from Monday 26 October until Thursday 29 October 1981. Ershov and Turski also attended after having spent the weekend with Dijkstra at his home in Nuenen.

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Dijkstra's Unifications versus the Case Distinctions of Irons & Feurzeig

Dated: 

1960

Toward the end of my paper `Dijkstra's Rallying Cry for Generalization ...' I briefly describe the work of Irons and Feurzeig. These two men had by 1960 also implemented ALGOL60's recursive procedure just like Dijkstra and Zonneveld. Their solution, however, was very different from the solution proposed by Dijkstra and Zonneveld.

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McKeag's account of T.H.E.

Dijkstra's Rallying Cry for Generalization is pleased to offer to its readers Chapter III of the book Studies in Operating Systems by R. M. McKeag and R. Wilson, edited by D H. R. Huxtable and published in 1976 by Academic Press:

T.H.E. Multiprogramming System (18.6 MiB PDF)
by R. M. McKeag

For personal use only. Republished here with the kind permission of McKeag and Fujitsu Services Ltd.

Human communication versus communication with a machine

Dated: 

October 1961

In his technical report (MR 34) of October 1961, Dijkstra made an analogy between human communication and communication with a machine and noted that the analogy is ineffective, an observation which complies with the earlier analogy he made between mathematics and programming, which he viewed to be effective.

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An analogy between mathematics and programming

Dated: 

October 1961

In his technical report (MR 34) of October 1961, Dijkstra explained why he viewed a good programming language to be one of a small number of very general concepts. To clarify, he used an analogy between mathematics and programming, an analogy which in later years would be scrutinized in several ways by his contemporaries. (See e.g. MacKenzie's 2004 book Mechanizing Proof: Computing, Risk, and Trust.)

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Trip to Scotland and Newcastle, September 1981

Dated: 

31 August -- 15 September, 1981

In the late summer of 1981, Dijkstra gave several talks in Scotland and Newcastle. Here is an overview of his trip:

+ The Marine Hotel in North Berwick. The host was Mr. Hannah of Burroughs. The audience consisted of 10 men from various Burroughs plants in Europe. Dijkstra lectured for five successive days, between 6 and 7 hours per day. The "standard surprise" from the audience was that the universal quantification over the empty set yields true.

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Trip to Marktoberdorf, Summer 1981

Dated: 

26 July -- 10 August, 1981

The theme of the International Summer School in Marktoberdorf was "Theoretical Foundations of Programming Methodology". The general pattern of the day was: two lectures — a break — two lectures — lunch — two lectures — break — discussion.

In his trip report, Dijkstra listed several speakers from that summer school:

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Summer school: Marktoberdorf, July 1971

Dated: 

2 August 1971

Roughly 80 participants from 15 countries participated in the 1971 summer school in Marktoberdorf. According to Dijkstra, some participants were very theoretically inclined, others more practically minded. Viewed from the present day, the following list of speakers at that summer school is impressive. Dijkstra attributed a theme to each speaker, with the exception of Perlis and Dahl:

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