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Communications of the ACM

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A letter from the ACM treasurer: ACM financial highlights


A vector space model for automatic indexing

In a document retrieval, or other pattern matching environment where stored entities (documents) are compared with each other or with incoming patterns (search requests), it appears that the best indexing (property) space is  …

Specifying queries as relational expressions: the SQUARE data sublanguage

This paper presents a data sublanguage called SQUARE, intended for use in ad hoc, interactive problem solving by non-computer specialists. SQUARE is based on the relational model of data, and is shown to be relationally complete …

A genealogy of control structures

The issue of program control structures has had a history of heated controversy. To put this issue on a solid footing, this paper reviews numerous theoretical results on control structures and explores their practical implications …

Practical syntactic error recovery

This paper describes a recovery scheme for syntax errors which provides automatically-generated high quality recovery with good diagnostic information at relatively low cost. Previous recovery techniques are summarized and empirical …

Backtrack programming techniques

The purpose of this paper is twofold. First, a brief exposition of the general backtrack technique and its history is given. Second, it is shown how the use of macros can considerably shorten the computation time in many cases …

A note on the set basis problem related to the compaction of character sets

This note discusses the reduction of the set basis problem to the clique cover problem.

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