the n-th symbolic power of P. Additive theory of ideals This result is the first in an area now known as the additive theory of ideals, which studies the ways of representing an ideal as the intersection of a special class of ideals. The decision on the "special class", e.g., primary ideals, is a problem in itself. In the case of non-commutative rings, the class of tertiary ideals is a useful substitute for the class of primary ideals. Notes References M. Atiyah, I.G. Macdonald, Introduction to Commutative Algebra, Addison–Wesley, 1994. Bourbaki, Algèbre commutative. , esp. section 3.3. . English translation in Communications in Computer Algebra 32/3 (1998): 8–30. External links Commutative algebra Theorems in ring theory Algebraic geometry