In this paper, it is shown that every orientable closed 3‐manifold maps with nonzero degree onto at most finitely many homeomorphically distinct irreducible nongeometric orientable closed 3‐manifolds. Moreover, given any nonzero integer, as a mapping degree up to sign, every orientable closed 3‐manifold maps with that degree onto only finitely many homeomorphically distinct orientable closed 3‐manifolds.

中文翻译：

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3流形之间的非零度映射的有限性

在本文中，我们证明了每个非零度可定向的封闭三流形映射到最多有限个同胚形独特的不可约非几何可定向的封闭三流形。此外，给定任何非零整数，作为直至符号的映射度，每个可定向的闭合3流形都以该度映射到有限的同胚同形不同的可定向闭合3流形上。