精華區beta Math 關於我們 聯絡資訊
We say that a closed subset C of a metric space X is nowhere-dense if and only if C contains no non -empty open subset of X. Prove the Baire Category Theorem: When X is a complete metric space, there does not exist a countable collection {C_γ包含於X:γ屬於Ν} of nowhere-dense closed subsets of X satisfying X = ∪C_γ, γ屬於Ν. -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 163.24.78.119