ListRelation Transitive Closure

rascal-0.40.17

Synopsis

Transitive closure on binary list relation values.

Syntax

Exp +

Types

Exp	Exp +
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>
]