An atomic formula or atom is simply a predicate applied to a tuple of terms; that is, an atomic formula is a formula of the form P (t1, …, tn) for P a predicate, and the tk terms.
All other well-formed formulae are obtained by composing atoms with logical connectives and quantifiers.
For example, the formula ∀x. P (x) ∧ ∃y. Q (y, f (x)) ∨ ∃z. R (z) contains the atoms
When all of the terms in an atom are ground terms, then the atom is called a ground atom or ground predicate.
Famous quotes containing the words atomic and/or formula:
“Take adultery or theft.
Merely sins.
It is evil who dines on the soul,
stretching out its long bone tongue.
It is evil who tweezers my heart,
picking out its atomic worms.”
—Anne Sexton (1928–1974)
“So, if we must give a general formula applicable to all kinds of soul, we must describe it as the first actuality [entelechy] of a natural organized body.”
—Aristotle (384–323 B.C.)