Description: Define the class of
converse reflexive relations. This is practically
dfcnvrefrels2 38052 (which uses the traditional subclass
relation ⊆) :
we use converse subset relation (brcnvssr 38030) here to ensure the
comparability to the definitions of the classes of all reflexive
(df-ref 23422), symmetric (df-syms 38066) and transitive (df-trs 38096) sets.
We use this concept to define functions (df-funsALTV 38205, df-funALTV 38206)
and disjoints (df-disjs 38228, df-disjALTV 38229).
For sets, being an element of the class of converse reflexive relations is
equivalent to satisfying the converse reflexive relation predicate, see
elcnvrefrelsrel 38060. Alternate definitions are dfcnvrefrels2 38052 and
dfcnvrefrels3 38053. (Contributed by Peter Mazsa,
7-Jul-2019.) |