This paper proves the following results: let X be a continuum, let k, m ∈ N, and let B ∈ C m (X), consider the continuous surjection f k : C k (X) → C k (X). We define the mapping B : C k (X) → C k+m (X): by B (A)...This paper proves the following results: let X be a continuum, let k, m ∈ N, and let B ∈ C m (X), consider the continuous surjection f k : C k (X) → C k (X). We define the mapping B : C k (X) → C k+m (X): by B (A) = f k (A) B. Then following assertions are equivalent: (1) The hyperspace C k (X) is g-contractible; (2) For each m ∈ N and for each B ∈ C m (X) the mapping B is a W -deformation in C k+m (X); (3) For each m ∈ N there exists B ∈ C m (X) such that the mapping B is a W -deformation in C k+m (X); (4) There exists m ∈ N such that for each B ∈ C m (X) the mapping B is a W -deformation in C k+m (X); (5) There exist m ∈ N and B ∈ C m (X) such that the mapping B is a W -deformation in C k+m (X).展开更多
基金Supported by the Department of Education Sichuan Province Foundation for Science Research(2006C041)Supported by the Anhui Provincial Foundation for Young Talents in College(2010SQRL158)
文摘This paper proves the following results: let X be a continuum, let k, m ∈ N, and let B ∈ C m (X), consider the continuous surjection f k : C k (X) → C k (X). We define the mapping B : C k (X) → C k+m (X): by B (A) = f k (A) B. Then following assertions are equivalent: (1) The hyperspace C k (X) is g-contractible; (2) For each m ∈ N and for each B ∈ C m (X) the mapping B is a W -deformation in C k+m (X); (3) For each m ∈ N there exists B ∈ C m (X) such that the mapping B is a W -deformation in C k+m (X); (4) There exists m ∈ N such that for each B ∈ C m (X) the mapping B is a W -deformation in C k+m (X); (5) There exist m ∈ N and B ∈ C m (X) such that the mapping B is a W -deformation in C k+m (X).
