[위상수학]topology질문입니다.

[체 게바라]

1.We say that a subset C of X is saturated if C contailns every set p^-1({y}) that it intersects

2.p is quotient map is equivalent to saying that p is continous and p maps saturated open sets of X to open sets of Y.

1.은 정의인데 saturated가 뭔지 잘 모르겠네요. 쉽게 설명좀..

2. quotient map을 saturated를 이용하여 설명한건데 이것도 좀 설명해주세요.

출처는 munkres/topology