2.7 Partial Orders and Equivalence

Relational Properties


For each of the following relations on people, decide whether the relation is reflexive, irreflexive, antisymmetric, or transitive:

  1. "are the same age"


  2. "is younger than"

    This relation is actually asymmetric - different people cannot be younger than each other.

  3. "have the same parents"


  4. "is a descendent of"

    This relation is irreflexive because a person is not considered to be his/her own descendent.

  5. "have a parent in common"

    This relation is not antisymmetric: different brothers have a parent in common.