A formula is in * standard form* after it has been converted to prenex
normal form, Skolemized, and converted into conjunctive normal form.
The result is a conjunction of * clauses*, each of which is a disjunction
of literals.

Example: ``Every man loves some woman.''

*&forall x [Man(x) &rarr &exist y [Woman(y) &and Loves(x,y)]]*

This is Skolemized as:

*Man(x) &rarr [Woman(lover(x)) &and Loves(x,lover(x))]*

Converted to CNF, it becomes:

*(¬ Man(x) &or Woman(lover(x))) &and
(¬ Man(x) &or Loves(x,lover(x)))*

Since we know where the *&and* and *&or* are in CNF, we can eliminate
them and represent clauses in list form in Lisp. Note that we have
eliminated all of the algebraic structure in the formulas except for *¬*.

( ( (not (man x)) (woman (lover x)) ) ( (not (man x)) (loves x (lover x)) ) )