摘要
Let P be a pseudo-arc in 2-sphere S<sup>2</sup>. A homeomorphism h : P →→ P is called essentially extendable iff there exists an imbedding φ:P → S<sup>2</sup> such that the homeomorphism φ hφ<sup>-1</sup>: φ（P）→φ（P）can be extended to S<sup>2</sup>.
基金
Project supported by the National Natural Science Foundation of China
