Guarded Commands, Nondeterminacy and Formal Derivation of Programs So-called "guarded commands" are introduced as a building block for alternative and repetitive constructs that allow nondeterministic program components for which at least the activity evoked, but possible even the final state, is not necessarily uniquely determined by the initial state. For the formal derivation of programs expressed in terms of these constructs, a calculus will be shown. CACM August, 1975 Dijkstra, E. W. programming languages, sequencing primitives, program semantics, programming language semantics, nondeterminacy, case-construction, repetition, termination, correctness proof, derivation of programs, programming methodology 4.20 4.22 CA750803 JB January 6, 1978 4:46 PM 249 4 2732 254 4 2732 272 4 2732 1102 4 2732 1109 4 2732 1140 4 2732 1188 4 2732 1306 4 2732 1464 4 2732 1491 4 2732 1767 4 2732 1781 4 2732 1787 4 2732 1949 4 2732 321 4 2732 2021 4 2732 2059 4 2732 2126 4 2732 2222 4 2732 2227 4 2732 2315 4 2732 2326 4 2732 2470 4 2732 435 4 2732 437 4 2732 463 4 2732 483 4 2732 491 4 2732 2732 4 2732 2732 4 2732 2865 4 2732 2896 4 2732 2943 4 2732 560 4 2732 583 4 2732 3014 4 2732 3068 4 2732 3073 4 2732 3077 4 2732 3143 4 2732 627 4 2732 631 4 2732 632 4 2732 642 4 2732 644 4 2732 653 4 2732 680 4 2732 761 4 2732 762 4 2732 763 4 2732 123 4 2732 140 4 2732 919 4 2732 989 4 2732 196 5 2732 1834 5 2732 2732 5 2732 2732 5 2732 2732 5 2732 2896 5 2732 2972 5 2732 3037 5 2732 3039 5 2732 3043 5 2732 3073 5 2732 196 6 2732 970 6 2732 1834 6 2732 2204 6 2732 2597 6 2732 2597 6 2732 2723 6 2732 2723 6 2732 2732 6 2732 2732 6 2732 2732 6 2732 2732 6 2732 2732 6 2732 2732 6 2732 2738 6 2732 2896 6 2732 2927 6 2732 799 6 2732