在射影几何里,当你学完了一维射影对应和透视对应以后,接着而来的内容就是一维射影对应的特殊情况——对合对应,读者学到这一概念时,往往有些费劲,这的确是射影几何里一个重点,也是一个难点,究竟如何突出这个重点,突破这个难点,确是值得注意的问题。根据本人教学的体会,必须本看由浅入深、由近及远、理论结合实际的原则。首先应该引导读者深入地认识建立对合概念的这个基础,然后在这个基础上,采 In projective geometry, when you finish the one-dimensional projective correspondence and the perspective correspondence, the ensuing content is the special case of a one-dimensional projective - the co-co-ordinates, readers often find it difficult to learn the concept, which Is indeed a focus of projective geometry, but also a difficult point, how to highlight this focus, to break through this difficulty is indeed a problem worth noting. According to my own teaching experience, we must see the light from the deep, from near and far, the theory combined with the actual principle. First of all, we should guide the reader to understand deeply the foundation of establishing the concept of co-integration, and then on this basis,