# Semantics of Ampersand

## (under construction)

Given:

1. a set of concepts C
2. a set of relations R. Every element of R has shape r[P*Q], in which r is called the name, P is called the source, and Q is called the target.
3. r[P*Q] in R implies that P in C and Q in C.
4. four predicates on relations, uni, inj, tot, sur.
5. a set of tables T
6. a set of attributes A. Every element of A has shape a<t,c>, in which a is called the name, t is called the table, and c is called the type.
7. a<t,c> in A implies that t in T and c in C.