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ListRelation Transitive Closure

rascal-0.34.0

Synopsis

Transitive closure on binary list relation values.

Syntax

Exp +

Types

ExpExp +
lrel[T₁, T₂]lrel[T₁, T₂]

Description

Returns the transitive closure of a binary listrelation. Transitive closure is defined by repeated composition of a relation. If we define for a given relation R:

  • R₁ = R
  • R₂ = R o R
  • R₃ = R o R₂
  • ...

then the transitive closure R+ can be defined as

  • R+ = R₁ + R₂ + R₃ + ...

Examples

rascal>[<1,2>, <2,3>, <3,4>]+;
lrel[int,int]: [
<1,2>,
<2,3>,
<3,4>,
<1,3>,
<2,4>,
<1,4>
]