| Description: Define the class of
converse reflexive relations. This is practically
dfcnvrefrels2 38929 (which uses the traditional subclass
relation ⊆) :
we use converse subset relation (brcnvssr 38907) here to ensure the
comparability to the definitions of the classes of all reflexive
(df-ref 23470), symmetric (df-syms 38943) and transitive (df-trs 38977) sets.
We use this concept to define functions (df-funsALTV 39087, df-funALTV 39088)
and disjoints (df-disjs 39110, df-disjALTV 39111).
For sets, being an element of the class of converse reflexive relations is
equivalent to satisfying the converse reflexive relation predicate, see
elcnvrefrelsrel 38937. Alternate definitions are dfcnvrefrels2 38929 and
dfcnvrefrels3 38930. (Contributed by Peter Mazsa,
7-Jul-2019.) |
