Lascar and Morley ranks differ in differentially closed fields

We note here, in answer to a question of Poizat, that the Morley and Lascar ranks need not coincide in differentially closed fields. We will approach this through the (perhaps) more fundamental issue of the variation of Morley rank in families. We will be interested here only in sets of finite Morl...

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Main Authors: Hrushovski, E, Scanlon, T
Format: Journal article
Published: Association for Symbolic Logic 1999
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author Hrushovski, E
Scanlon, T
author_facet Hrushovski, E
Scanlon, T
author_sort Hrushovski, E
collection OXFORD
description We note here, in answer to a question of Poizat, that the Morley and Lascar ranks need not coincide in differentially closed fields. We will approach this through the (perhaps) more fundamental issue of the variation of Morley rank in families. We will be interested here only in sets of finite Morley rank. Section 1 consists of some general lemmas relating the above issues. Section 2 points out a family of sets of finite Morley rank, whose Morley rank exhibits discontinuous upward jumps. To make the base of the family itself have finite Morley rank, we use a theorem of Buium.
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spelling oxford-uuid:cb59719a-b2fb-437e-80a2-97fea02970012022-03-27T07:14:11ZLascar and Morley ranks differ in differentially closed fieldsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:cb59719a-b2fb-437e-80a2-97fea0297001Symplectic Elements at OxfordAssociation for Symbolic Logic1999Hrushovski, EScanlon, T We note here, in answer to a question of Poizat, that the Morley and Lascar ranks need not coincide in differentially closed fields. We will approach this through the (perhaps) more fundamental issue of the variation of Morley rank in families. We will be interested here only in sets of finite Morley rank. Section 1 consists of some general lemmas relating the above issues. Section 2 points out a family of sets of finite Morley rank, whose Morley rank exhibits discontinuous upward jumps. To make the base of the family itself have finite Morley rank, we use a theorem of Buium.
spellingShingle Hrushovski, E
Scanlon, T
Lascar and Morley ranks differ in differentially closed fields
title Lascar and Morley ranks differ in differentially closed fields
title_full Lascar and Morley ranks differ in differentially closed fields
title_fullStr Lascar and Morley ranks differ in differentially closed fields
title_full_unstemmed Lascar and Morley ranks differ in differentially closed fields
title_short Lascar and Morley ranks differ in differentially closed fields
title_sort lascar and morley ranks differ in differentially closed fields
work_keys_str_mv AT hrushovskie lascarandmorleyranksdifferindifferentiallyclosedfields
AT scanlont lascarandmorleyranksdifferindifferentiallyclosedfields