Definition of Unification For First-order Logic
Let p and q be sentences in first-order logic.
- UNIFY(p,q) = U where subst(U,p) = subst(U,q)
Where subst(U,p) means the result of applying substitution U on the sentence p. Then U is called a unifier for p and q. The unification of p and q is the result of applying U to both of them.
Let L be a set of sentences, for example, L = {p,q}. A unifier U is called a most general unifier for L if, for all unifiers U' of L, there exists a substitution s such that applying s to the result of applying U to L gives the same result as applying U' to L:
- subst(U',L) = subst(s,subst(U,L)).
Read more about this topic: Unification (computer Science)
Famous quotes containing the words definition of, definition and/or logic:
“I’m beginning to think that the proper definition of “Man” is “an animal that writes letters.””
—Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)
“The physicians say, they are not materialists; but they are:MSpirit is matter reduced to an extreme thinness: O so thin!—But the definition of spiritual should be, that which is its own evidence. What notions do they attach to love! what to religion! One would not willingly pronounce these words in their hearing, and give them the occasion to profane them.”
—Ralph Waldo Emerson (1803–1882)
“Though living is a dreadful thing
And a dreadful thing is it
Life the niggard will not thank,
She will not teach who will not sing,
And what serves, on the final bank,
Our logic and our wit?”
—Philip Larkin (1922–1986)