High Quality Content by WIKIPEDIA articles! In a mathematical proof, the therefore sign (?) is a symbol that is sometimes placed before a logical consequence, such as the conclusion of a syllogism.[citation needed] The symbol consists of three dots placed in an upright triangle and is read therefore. It is Unicode character U+2234 and on some systems may be entered using ALT-8756 (the decimal version of 2234). While it is not generally used in formal writing, it is often used in mathematics and shorthand. According to Cajori, A History of Mathematical Notations, the therefore sign was first used by Johann Rahn in 1659, in the original German edition of his book Teutsche Algebra.

Данное издание не является оригинальным. Книга печатается по технологии принт-он-деманд после получения заказа.