In a formal grammar, an erasing rule is a rule which maps a string of symbols to the empty string (ε).
Formally, an erasing rule is an ε-production, like
Famous quotes containing the word rule:
“After all, the practical reason why, when the power is once in the hands of the people, a majority are permitted, and for a long period continue, to rule is not because they are most likely to be in the right, nor because this seems fairest to the minority, but because they are physically the strongest. But a government in which the majority rule in all cases cannot be based on justice, even as far as men understand it.”
—Henry David Thoreau (1817–1862)