Form equivalence class Howard-Rubin Number: 88
Statement:
For any cardinal \(m\), there is a unary algebra \(\frak A = \langle A,F\rangle\) (only unary and nullary operations) and a proper subalgebra \(\frak D\) of \(\frak A^{2}\) such that \(\frak A^{2}\) has exactly four subalgebras, \(\frak A\), \(\emptyset\), \(\frak D\) and \(\frak D^{*}= \{(s,t): (t,s)\in\frak D\}\).
Howard-Rubin number: 88 D
Citations (articles):
Lampe [1974]
Subalgebra lattices of unary algebras and an axiom of choice
Connections (notes):
References (books):
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