# Frases de Kenneth Iverson

## Kenneth Iverson

**Data de nascimento:** 17. Dezembro 1920**Data de falecimento:** 19. Outubro 2004

Kenneth Eugene Iverson foi um matemático canadense.

Desenvolveu as linguagens de programação APL e J. Em 1979 recebeu o Prêmio Turing.A Iverson se atribui a definição das funções piso e teto pelos termos floor e ceiling, com seus respectivos símbolos ⎣ ⎦ e ⎡ ⎤. Outra notação a ele atribuída são os chamados colchetes de Iverson.

== Referências ==

### Autores parecidos

### Citações Kenneth Iverson

### „The initial motive for developing APL was to provide a tool for writing and teaching. Although APL has been exploited mostly in commercial programming, I continue to believe that its most important use remains to be exploited: as a simple, precise, executable notation for the teaching of a wide range of subjects.“

— Kenneth E. Iverson

"A Personal View of APL", IBM Systems Journal, 30 (4), 1991

### „It is important to distinguish the difficulty of describing and learning a piece of notation from the difficulty of mastering its implications. [... ] Indeed, the very suggestiveness of a notation may make it seem harder to learn because of the many properties it suggests for exploration.“

— Kenneth E. Iverson

§5.2

### „Overemphasis of efficiency leads to an unfortunate circularity in design: for reasons of efficiency early programming languages reflected the characteristics of the early computers, and each generation of computers reflects the needs of the programming languages of the preceding generation.“

— Kenneth E. Iverson

§5.4

### „I was appalled to find that the mathematical notation on which I had been raised failed to fill the needs of the courses I was assigned, and I began work on extensions to notation that might serve. In particular, I adopted the matrix algebra used in my thesis work, the systematic use of matrices and higher-dimensional arrays (almost) learned in a course in Tensor Analysis rashly taken in my third year at Queen’s, and (eventually) the notion of Operators in the sense introduced by Heaviside in his treatment of Maxwell’s equations.“

— Kenneth E. Iverson

"Kenneth E. Iverson" http://keiapl.info/rhui/autobio.htm, autobiographical sketch from an unfinished work (ca. 2004), on his experience at Harvard with "a Masters program in Automatic Data Processing in 1955; in effect, the first computer science program."

### „The practice of first developing a clear and precise definition of a process without regard for efficiency, and then using it as a guide and a test in exploring equivalent processes possessing other characteristics, such as greater efficiency, is very common in mathematics. It is a very fruitful practice which should not be blighted by premature emphasis on efficiency in computer execution.“

— Kenneth E. Iverson

§5.4

### „Although mathematical notation undoubtedly possesses parsing rules, they are rather loose, sometimes contradictory, and seldom clearly stated. [... ] The proliferation of programming languages shows no more uniformity than mathematics. Nevertheless, programming languages do bring a different perspective. [... ] Because of their application to a broad range of topics, their strict grammar, and their strict interpretation, programming languages can provide new insights into mathematical notation.“

— Kenneth E. Iverson

Ch. 10, §D