The Kobayashi distance induces the standard topology
The Kobayashi distance induces the standard topology
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小林距离推导出标准拓扑
DOI:
10.1090/s0002-9939-1972-0306545-x
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发表时间:
1972
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影响因子:
--
通讯作者:
Theodore J. Barth
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文献类型:
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作者:
Theodore J. Barth
The Kobayashi pseudodistance on a connected complex space is continuous with respect to the standard topology. IC this pseudodistance is an actual distance, it induces the standard topology. Let X be a connected (reduced) complex space. The Kobayashi pseudodistance dx(p, q) between points p and q of X is defined as follows ([6, p. 462], [7, pp. 97-98]). Let p denote the distance defined by the PoincareBergman metric on the open unit disk D in the complex plane. Choose points P PO,PloP' . Pk-1 pk=q of X, points a1,, * * , ak, bl, * * *, bk of D, and holomorphic maps fl, *, *fk from D into X such that fj(aj)= Pj-l and fj(bj)=pj for j= 1, , k. Then dx(p, q) is defined to be the infimum of the numbers p(a,, bl)+... + p(ak, bk) taken over all such finite chains joining p and q. Clearly dx is a pseudodistance on X. In case dx is an actual distance we will show that it induces the standard topology, i.e., the topology underlying the given complex structure on X. Several authors have tacitly used this fact; cf. [1, Proposition 3.8, pp. 68-69], [4, Proposition 1, pp. 50-51], [5, Theorems 2 and 3, pp. 590-591], [6, Theorem 3.4, pp. 465-466], [8, Theorem 1, pp. 11-12]. The only published proof, however, seems to be the one given by H. L. Royden [9, Theorem 2, pp. 133-134] for complex manifolds. Our proof uses only three elementary facts about the Kobayashi pseudodistance: if f: Y--Z is a holomorphic map, it is distance decreasing in the sense that dz(f(p),f (q))<dy(p, q) for all p and q in Y [6, Proposition 2.1, p. 462]; dD= p [6, Proposition 2.2, p. 462]; if Q=Dn is a polydisk, then dQ is continuous with respect to the standard topology on Q [7, p. 47]. In particular, we avoid Royden's differential metric. THEOREM. Let X be a connected complex space. Then the Kobayashi pseudodistance dx is continuous. If dx is an actual distance, it induces the standard topology on X. Received by the editors December 30, 1971. AMS 1970 subject classifications. Primary 32H15, 32H20.