四个实线圆相交于ABCDEFG 七个点，证明过ADC、AEF、DEG、CFG的四个虚线圆交于一点

天山草

这个结论叫做克里福德定理。

dodonaomikiki

由此可见，
西洋人对几何之研究，
还是比较深~~~CLIFFORD   circle   theorem从未耳闻！



涨见识！

dodonaomikiki

https://wenku.baidu.com/view/6896b5e24973f242336c1eb91a37f111f0850de4.html?_wkts_=1684004980934&bdQuery=CLIFFORD+circle+theorem

这里看来，有很多陈述！

dodonaomikiki

William Clifford (1845-1879) was an important mathematician of his day. He is most remembered today for his invention of Clifford algebras, which are fundamental in modern differential geometry and mathematical physics. His ideas on the connection between energy and matter and the curvature of space were important in the eventual formulation of general relativity. Clifford was particularly interested in non-Euclidean geometry. However, in his relatively brief career, he made contributions to diverse fields of mathematics: elliptic functions, Riemann surfaces, biquaternions, motion in Euclidean and non-Euclidean space, spaces of constant curvature, syzygies, and so on. He was also well-known as a teacher and for his ideas on the philosophy of science. This work covers the life and mathematical work of Clifford, from his early education at Templeton (Exeter) to King's College (London), to Trinity (Cambridge) and ultimately to his professorship at University College (London)--a post which he occupied until the time of his death. Tucker discusses Clifford's Fellowship at the Royal Society and his Council post at the London Mathematical Society.

Mathematical Papers by William Kingdon Clifford by Robert Tucker. Oxford University Press

dodonaomikiki

由拉巴次仁老师的描述来看，
此定理的证明，
用初等几何学知识来搞，
存在一定困难！




这样一说，
也许就要引进高等几何观念以及高等几何知识

dodonaomikiki

刚刚阅读了一哈威廉姆克里福德，
很厉害呀~~~
发现了欧几里得平面里，存在着一串串连贯性的定理，
复杂性逐步递进佩服！



看来，
欧几里得平面中的定理，
类似一串串葡萄，存在着连贯性、复杂递进性