2. Let the inverse relation r c of r, r c ∩ r be included in the identity relation i, that is, for any
3.R^2
= { & lt2,2 & gt; ,& lt2,4 >,& lt2.6 & gt,& lt2,8 >,& lt3,3 & gt; ,<3 >, & lt4,4 >, & lt4,8 >, & lt6,6 >, & lt8,8 >} = r, that is, r 2 is included in r, (that is, for any.
R is reflexive, antisymmetric and transitive, so R is a partial order relation on A. 。