Path: news.ccsf.jp!norn-news!news-haigo!news.tkn.funabashi.chiba.jp!tomockey.ddo.jp!usenet.blueworldhosting.com!feeder01.blueworldhosting.com!feeder.erje.net!1.eu.feeder.erje.net!eternal-september.org!feeder.eternal-september.org!mx02.eternal-september.org!.POSTED!not-for-mail
From: "Kyoko Yoshida" <kyokoyoshida123@gmail.com>
Newsgroups: fj.sci.math
Subject: =?iso-2022-jp?B?UmU6IDIbJEJKUT90SiNBR0I/OWA8MCROOiwkTk8iQjNALSRLJEQbKEI=?=
	=?iso-2022-jp?B?GyRCJCQkRhsoQg==?=
Date: Wed, 25 Nov 2015 13:40:07 -0500
Organization: A noiseless patient Spider
Lines: 12
Message-ID: <n34v4o$hfi$1@dont-email.me>
References: <n2tmd3$ipd$1@dont-email.me> <2d3d66a2-c88e-4900-910f-fbff3ef1f46c@googlegroups.com> <n3350q$k0t$1@dont-email.me> <813983a2-fecc-4f73-8d1c-81a14a09052f@googlegroups.com>
Mime-Version: 1.0
Content-Type: text/plain;
	format=flowed;
	charset="iso-2022-jp";
	reply-type=original
Content-Transfer-Encoding: 7bit
Injection-Date: Wed, 25 Nov 2015 18:37:12 -0000 (UTC)
Injection-Info: mx02.eternal-september.org; posting-host="4ba9f85d5ba7b323c961c8234ad1b019";
	logging-data="17906"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1+18IsZrV6g3uSyD6wA0xgsrgJ/yvlcSic="
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5512
X-Antivirus-Status: Clean
X-Newsreader: Microsoft Outlook Express 6.00.2900.5512
X-Antivirus: avast! (VPS 151123-1, 2015/11/23), Outbound message
Cancel-Lock: sha1:dmXKHSTNjehcFtWTX8lGztUcj6Q=
X-Priority: 3
X-MSMail-Priority: Normal
Xref: news.ccsf.jp fj.sci.math:3908

ご回答誠に有難うございます。

>> x=x_0の時,y=y_0なら,yがx=x_0で連続であるとは,
>> For∀ε∈R^+,∃δ∈R^+;{y∈C;xy=0,|x-x_0|<δ}⊂{y∈C;|y-y_0|<ε}
>> という事だと思いますが。。
> x_0 = 0, y_0 = 0 においてそうなりますか.

そうなりませんし,
今,X⊂Cでfはf(x):={y∈R;xy=0}の意味(つまり,f:X→2^R)で
f:X→R;X∋∀x→f(x):={0} if x≠0, R if x=0となっているのでこのfは写像ではなく,対応なのではないでしょうか?
よってxy=0はyはx=0で不連続ですか。 


---
This email is free from viruses and malware because avast! Antivirus protection is active.
https://www.avast.com/antivirus