His conjecture, made in 1904, was that in this four-dimensional world, all closed three-dimensional surfaces that are simply connected could be transformed to look like a three-dimensional sphere.

他在1904年就提出猜想：在四维空间，所有单连通的封闭三维面都能转化为一个三维球体。

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As mathematicians say, “Every simply connected closed 3-manifold is homeomorphic to a 3-sphere.”

用数学语言表达就是“每个单连通3重（3-manifold）封闭体与一个三维球体同胚（homeomorphic）。”

youdao

As mathematicians say, "Every simply connected closed 3-manifold is homeomorphic to a 3-sphere."

用数学语言表达就是“每个单连通3重（3-manifold）封闭体与一个三维球体同胚（homeomorphic）。”

youdao

His conjecture, made in 1904, was that in this four-dimensional world, all closed three-dimensional surfaces that are simply connected could be transformed to look like a three-dimensional sphere.

ECONOMIST: Proof of the truth of the Poincar�� conjecture