fundamental group;
homology;
descriptive set theory;
SPACE;
D O I:
10.4064/fm232-1-3
中图分类号:
O1 [数学];
学科分类号:
0701 ;
070101 ;
摘要:
We show that the first homology group of a locally connected compact metric space is either uncountable or finitely generated. This is related to Shelah's well-known result (1988) which shows that the fundamental group of such a space satisfies a similar condition. We give an example of such a space whose fundamental group is uncountable but whose first homology is trivial, showing that our result does not follow from Shelah's. We clarify a claim made by Pawlikowski (1998) and offer a proof of the clarification.