 
Summary: Definition FS.1.1: x0y = x \ y y \ x. Precedence: 60.
Definition FS.1.2: x × y is the set of (z,w) such that z x and w y.
Precedence: 20.
Definition FS.2.1: A is a binary relation if and only if for every y A,
there exist z, w such that y = (z,w).
Definition FS.2.2: A is a ternary relation if and only if for every y A,
there exist z, w, u such that y = (z,w,u).
Definition FS.2.3: If R is a binary relation then the domain of R is the
set of x such that there exists y such that xRy. Otherwise the domain of R is
undefined.
Definition FS.2.4: If R is a binary relation then the range of R is the
set of y such that there exists x such that xRy. Otherwise the range of R is
undefined.
Definition FS.2.5: The field of R is the domain of R union the range of
R.
Definition FS.2.6: If R is a binary relation then the converse relation to
R is {(x, y) : yRx}. Otherwise the converse relation to R is undefined.
Definition FS.2.8: If R and S are binary relations then R S is the set
of (x,y) such that there exists z such that xRz and zSy. Otherwise R S is
undefined. Precedence: 10.
