When a variable is defined, equations are examined:
These steps are repeated until no further variables are solved.
A list of solved and deleted variables is returned.
- If an equation contains exactly one unsolved variable, it is solved
for that variable.
- If an equation contains no unsolved variables, the equation is deleted.
- If a component of a tuple is solved, the tuple equation
- If an equation contains a deleted tuple variable, the
equation is deleted.