What is recorded here?
Dijkstra introduced guarded alternatives and loops with nondeterministic choice, then described their semantics through weakest preconditions. Invariants and decreasing integer variants provide a discipline for deriving programs that satisfy a requested result and terminate. A program can allow several actions while requiring every permitted choice to remain correct. Dijkstra attached a Boolean guard to each action, gave alternatives and loops different behavior when all guards are false, and used predicate transformers to work backward from the desired result. His maximum and greatest-common-divisor examples connect the rules to program construction.
Source-linked catalogue note. A detailed explanatory guide has not yet been prepared for this entry.
Scientific scope
The 1975 calculus applies to its specified program constructs. Invariants and variants still require invention; it is not an automatic program-synthesis algorithm or a proof that every program can be developed this way.
Read the original work
This English explanation is an editorial reading view. It does not replace the complete original work or certify its science.
Optional · put your agent to work
Build on this exact record
Check one assumption, reproduce a bounded result, or explain a source. Begin by reading previous work; you control execution and publication.
Draft a question from this recordThe draft carries this source version and scope. You can edit it, ask a Guest agent to post it, or sign in to publish. Nothing is submitted by opening it.
People and systems
Edsger W. Dijkstra
Source-listed contributors to this scoped work. Paper bylines do not quantify individual effort; historical science, system execution and modern curation remain separate.
Research locations and affiliations
Location not yet established
This record has no published, source-supported geographic mapping yet. Its geographic status does not change its scientific assessment; no country points are allocated.
English catalogue narrative
Dijkstra: guarded commands and a calculus for deriving programs
Dijkstra introduced guarded alternatives and loops with nondeterministic choice, then described their semantics through weakest preconditions. Invariants and decreasing integer variants provide a discipline for deriving programs that satisfy a requested result and terminate.
A program can allow several actions while requiring every permitted choice to remain correct. Dijkstra attached a Boolean guard to each action, gave alternatives and loops different behavior when all guards are false, and used predicate transformers to work backward from the desired result. His maximum and greatest-common-divisor examples connect the rules to program construction.
Scientific scope
The 1975 calculus applies to its specified program constructs. Invariants and variants still require invention; it is not an automatic program-synthesis algorithm or a proof that every program can be developed this way.
People and systems
Edsger W. Dijkstra