subuppersemilattice

English

Etymology

sub- +‎ uppersemilattice

Noun

subuppersemilattice (plural subuppersemilattices)

1. (mathematics) A sub-semilattice of an uppersemilattice.
   • 1988, Manuel Lerman, Richard A. Shore-, “Decidability and invariant classes for degree structures”, in Transactions of the American Mathematical Society, volume 310, number 2:

     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 ...

   • 2016, James Barnes, “On the decidability of the $\Sigma _{2}$ theories of the arithmetic and hyperarithmetic degrees as uppersemilattices”, in arXiv‎^[1]:

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