Units of paper quantity Simon Winchester, in "The Surgeon of Crowthorne", cites a specific number, defining quire as "a booklet eight pages thick." Several European words for quire keep the meaning of "book of paper": Ger. "Buch von Papier", Dan. "bog papir", Du. "bock papier". In blankbook binding, "quire" is a term indicating 80 pages. A ream of paper is a quantity of sheets of the same size and quality. International standards organizations define the ream as 500 identical sheets. This ream of 500 sheets (20 quires of 25 sheets) is also known as a 'long' ream, and is gradually replacing the old value
Many-one reduction in: We say that a class C of languages (or a subset of the power set of the natural numbers) is "closed under many-one reducibility" if there exists no reduction from a language in C to a language outside C. If a class is closed under many-one reducibility, then many-one reduction can be used to show that a problem is in C by reducing a problem in C to it. Many-one reductions are valuable because most well-studied complexity classes are closed under some type of many-one reducibility, including P, NP, L, NL, co-NP, PSPACE, EXP, and many others. These classes