Usurpation of Qi by Tian the name "Qi" for its realm after the usurpation. For historiographical purposes, pre-usurpation Qi is referred to as "Jiang Qi" (姜齊), and post-usurpation Qi is referred to as "Tian Qi" (田齊). Qi was originally ruled by the Jiang clan, the descendants of Jiang Ziya. In 672 BCE, Prince Chen Wan of the State of Chen fled to Qi following political unrest in his native state and became the progenitor of the Chen clan of Qi, which was later known as Tian. By 545 BCE, the Tian clan was one of the strongest families in Qi. Tian Huanzi, in conjunction with
What Is Mathematics? Expectations" by Charles Dickens. According to Constance Reid, Courant finalized the title after a conversation with Thomas Mann. What Is Mathematics? What Is Mathematics? is a mathematics book written by Richard Courant and Herbert Robbins, published in England by Oxford University Press. It is an introduction to mathematics, intended both for the mathematics student and for the general public. First published in 1941, it discusses number theory, geometry, topology and calculus. A second edition was published in 1996 with an additional chapter on recent progress in mathematics, written by Ian Stewart. The book was based on Courant's course material. Although