Relational expressions are a compact notation for combining relational operations that go together. A relational expression results in a boolean result.
The operations that can be combined are the relational operations.
Order of operations
<
,<=
,>
and>=
=
and!=
Example
The TTable of
a < b = b > c
is
Expression  Operation 

a < b = b > c 

t1 = b > c 
t1 = a < b 
t1 = t2 
t2 = b > c 
t3 
t3 = t1 = t2 
The TForm is
t1 = a < b
t2 = b > c
t3 = t1 = t2
For more information about TTables and TForms, see TTables.