subuppersemilattice

plural subuppersemilattices

1. mathematicsA sub-semilattice of an uppersemilattice.

   First, given any finite subuppersemilattice U ot 3[0,0'] with top element 0' and an isomorphism type V of a poset extending U consistently with its structure as an usl such that V and U have the same top element and V is an end extension of ...

   1988, Manuel Lerman, Richard A. Shore-, “Decidability and invariant classes for degree structures”, in Transactions of the American Mathematical Society, volume 310, number 2

   1 more example

   This is achieved by using Kumabe-Slaman forcing - along with other known results - to show that given finite uppersemilattices #92;mathcal#123;M#125; and #92;mathcal#123;N#125;, where #92;mathcal#123;M#125; is a subuppersemilattice of #92;mathcal#123;N#125;, then for both degree structures, every embedding of #92;mathcal#123;M#125; into the structure extends to one of #92;mathcal#123;N#125; iff #92;mathcal#123;N#125; is an end-extension of #92;mathcal#123;M#125;..

   2016, James Barnes, “On the decidability of the Σ₂ theories of the arithmetic and hyperarithmetic degrees as uppersemilattices”, in arXiv