Let us consider first a regular tetrahedron whose corners will
have attached to them the TQFT
symbols representing a TQF state in terms of so-called `j-symbols' as further detailed next. The vertices of the tetrahedron are located at the points
,
,
, and
, that will be labeled, respectively, as
.
Definition 1.1
A
quantum field (QF) state 
provides a total order denoted by

on the
vertices of the tetrahedron, and thus also assigns a `direction' to each edge of the tetrahedron-from the
apparently `smaller' to the apparently `larger' vertices; a QF state also labels each edge

,
by an element

of

, which is a
distinguished basis of a fusion algebra

, that is, a finite-dimensional, unital, involutive algebra over

-the field of complex numbers. Moreover, the QF state assigns an element

-called an intertwiner- of a
Hilbert space
to each face

of the tetrahedron, such that