Type-amalgamation properties and polygroupoids in stable theories

John Goodrick, Byunghan Kim, Alexei Kolesnikov

Research output: Contribution to journalArticle

3 Citations (Scopus)


We show that in a stable first-order theory, the failure of higher dimensional type amalgamation can always be witnessed by algebraic structures that we call n-ary polygroupoids. This generalizes a result of Hrushovski in [16] that failures of 4-amalgamation are witnessed by definable groupoids (which correspond to 2-ary polygroupoids in our terminology). The n-ary polygroupoids are definable in a mild expansion of the language (adding a predicate for a Morley sequence).

Original languageEnglish
Article number1550004
JournalJournal of Mathematical Logic
Issue number1
Publication statusPublished - 2015 Jun 10

All Science Journal Classification (ASJC) codes

  • Logic

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