02158  Concurrent Programming - Errata and clarifying remarks
Technical University of Denmark DTU
02158 Concurrent Programming        Fall 2024
Errata and clarifying remarks
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This page lists corrections and remarks to the material handed out for the course.

For errata to Andrews' textbook, see also his own comprehensive errata list.

Errata

[Andrews] Page 95, line 6 from bottom The first three are safety properties, the fourth is a liveness property.   should be
The first one is a safety property, the last three are liveness properties.

Correspondingly, the discussion following in the paragraph is not quite right and should be ignored.

Contributions are appreciated!

Remarks

1. There is a slight deviation in the definitions of critical references in [Basic] and [Andrews] although they express the same idea. For an assignment statement, x : = e, Andrews in Def. (2.2) at page 52, only considers the critical references within the expression e and then uses cases on x to determine whether the whole statement satisfies the At-most-once-property. Ie., Andrews does not explicitly consider whether the assignment to x is critical or not.

In [Basic] the assignment to x may itself be considered a critical reference (viz. if x is read by other processes). This way the definition is simplified to the rule of at-most-one-critical-reference.

In any case of discrepancy between [Andrews] and [Basic], the notions of [Basic] are used in this course.

Hans Henrik Løvengreen, Sep 6, 2024