<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><span class="">皆様，</span><span class=""><br class=""></span><span class=""><br class=""></span><span class="">名古屋大学の木原貴行です．この度，コネチカット大学の Linda Brown Westrick 氏の名古屋訪問の折に，下記の要領で名古屋ロジックセミナーを開催することとなりました．多数のご参加をお待ちしております．</span><span class=""><br class=""></span><span class=""><br class=""></span><span class="">名古屋ロジックセミナー</span><span class=""><br class=""></span><span class=""><a href="http://www.math.mi.i.nagoya-u.ac.jp/~kihara/logic-seminar.html" class="">http://www.math.mi.i.nagoya-u.ac.jp/~kihara/logic-seminar.html</a></span><span class=""><br class=""></span><span class=""><br class=""></span><span class="">日時：8月24日 (木) 15:30〜</span><span class=""><br class=""></span><span class="">場所：名古屋大学大学院情報学研究科棟 314室</span><span class=""><br class=""></span><span class=""><br class=""></span><span class=""></span><span class="">講演者：</span><span class="">Linda Brown Westrick (コネチカット大学)<br class="">題目<span class="Apple-tab-span" style="white-space:pre"> </span>Uncountable free abelian groups via admissible computability<br class="">概要<span class="Apple-tab-span" style="white-space:pre"> </span>One way to study structures of uncountable cardinality κ is to generalize the notion of computation. Saying that a subset of κ is κ-c.e. if it is Σ^0_1 definable (with parameters, in the language of set theory) over L_κ provides the notion of κ-computability. We may also quantify over subsets of L_κ, providing a notion of a κ-analytic set (here we assume V=L). In this setting, we consider the difficulty of recognizing free groups and the complexity of their bases. For example, if κ is a successor cardinal, the set of free abelian groups of size κ is Σ^1_1-complete. The resolution of questions of this type is more complex for other κ, and a few questions remain open. This is joint work with Greenberg and Turetsky.</span><div class=""><div class="">
<div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><br class="Apple-interchange-newline">--------</div><div class=""><br class=""></div><div class="">Takayuki Kihara</div><div class="">Graduate School of Informatics, Nagoya University, Japan</div><div class="">URL: <a href="http://math.mi.i.nagoya-u.ac.jp/~kihara/" class="">http://math.mi.i.nagoya-u.ac.jp/~kihara/</a></div><div class="">Email: <a href="mailto:kihara@i.nagoya-u.ac.jp" class="">kihara@i.nagoya-u.ac.jp</a></div><div class=""><br class=""></div></div><br class="Apple-interchange-newline" style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><br class="Apple-interchange-newline">
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