Programming language constructs for expressing parallelism

PARBEGIN-PAREND

The reverse is not true. PARBEGIN and PAREND cannot be used to express some precedence graphs. In particular, our first example can only be partially realized using PARBEGIN and PAREND:

  S1;
  PARBEGIN
    S2; S3
  PAREND;
  PAREBEGIN
    S4; S5
  PAREND;
  S6;