Let A and B stand for the two kinds of words.
Let A and B be arbitrary formula of a formal language .
Specifically, let A and B be any two sets.
Let B be the number of these assignments which result in blocking.
Yet another possibility would be to let B be .
Let B be the amount of the initial bet.
Let A and B be any two expressions of the primary algebra.
Let A and B be some matrices which elements are complex numbers.
Let B be the jth line of the second file.
Let A and B be two fuzzy subsets of X.