Deprecated: $wgMWOAuthSharedUserIDs=false is deprecated, set $wgMWOAuthSharedUserIDs=true, $wgMWOAuthSharedUserSource='local' instead [Called from MediaWiki\HookContainer\HookContainer::run in /var/www/html/w/includes/HookContainer/HookContainer.php at line 135] in /var/www/html/w/includes/Debug/MWDebug.php on line 372
Almost free splitters - MaRDI portal

Deprecated: Use of MediaWiki\Skin\SkinTemplate::injectLegacyMenusIntoPersonalTools was deprecated in Please make sure Skin option menus contains `user-menu` (and possibly `notifications`, `user-interface-preferences`, `user-page`) 1.46. [Called from MediaWiki\Skin\SkinTemplate::getPortletsTemplateData in /var/www/html/w/includes/Skin/SkinTemplate.php at line 691] in /var/www/html/w/includes/Debug/MWDebug.php on line 372

Deprecated: Use of MediaWiki\Skin\BaseTemplate::getPersonalTools was deprecated in 1.46 Call $this->getSkin()->getPersonalToolsForMakeListItem instead (T422975). [Called from Skins\Chameleon\Components\NavbarHorizontal\PersonalTools::getHtml in /var/www/html/w/skins/chameleon/src/Components/NavbarHorizontal/PersonalTools.php at line 66] in /var/www/html/w/includes/Debug/MWDebug.php on line 372

Deprecated: Use of QuickTemplate::(get/html/text/haveData) with parameter `personal_urls` was deprecated in MediaWiki Use content_navigation instead. [Called from MediaWiki\Skin\QuickTemplate::get in /var/www/html/w/includes/Skin/QuickTemplate.php at line 131] in /var/www/html/w/includes/Debug/MWDebug.php on line 372

Almost free splitters

From MaRDI portal
Publication:6501526

arXivmath/9910161MaRDI QIDQ6501526

Author name not available (Why is that?)


Abstract: Let R be a subring of the rationals. We want to investigate self splitting R-modules G that is Ext_R(G,G)=0 holds. For simplicity we will call such modules splitters. Our investigation continues math.LO/9910159. In math.LO/9910159, we answered an open problem by constructing a large class of splitters. Classical splitters are free modules and torsion-free, algebraically compact ones. In math.LO/9910159 we concentrated on splitters which are larger then the continuum and such that countable submodules are not necessarily free. The `opposite' case of aleph_1-free splitters of cardinality less or equal to aleph_1 was singled out because of basically different techniques. This is the target of the present paper. If the splitter is countable, then it must be free over some subring of the rationals by a result of Hausen. We can show that all aleph_1-free splitters of cardinality aleph_1 are free indeed.





Mathematics Subject Classification ID

No records found.








This page was built for publication: Almost free splitters

Report a bug (only for logged in users!)Click here to report a bug for this page (MaRDI item Q6501526)

Retrieved from "https://mardi.schubotz.org/w/index.php?title=Publication:6501526&oldid=37961701"
Powered by MediaWiki