Brainstorming.
/*
A record is a vector composed of varying datatypes/domains. R = integer ? varchar(200) ? date R = (i,v,d) R= (1, "Hello world!", 20131012)
R1=(1, "Hello world!", 19771012) R2=(2, "Farewell, cruel world!", 20891012)
Records are elements. A group of records are a set: A= {R1,R2}
A = {x | x.i=1 or x.v="Hello world!"}
{} empty set -- U+2205 NULL A intersect B -- n U+2229 A union B -- U+222A x in A -- U+2208 A cross B -- U+2297 A left normal factor semidirect product B -- U+22C9 A right normal factor semidirect product B -- U+22CA
B minus A -- U+2216 A subset B -- U+2282
? */
See: http://en.wikibooks.org/wiki/Set_Theory/Sets http://www.w3.org/TR/xml-entity-names/isoamsb.html