Form equivalence class Howard-Rubin Number: 0

Statement:

For every class \(K\) of similar algebras \(SP\ K \supseteq PS\ K\). (For any class \(K\) of similar algebras, \(S\ K\) is the class of all subalgebras of elements of \(K\) (not closed under isomorphism) and\(P\ K\) is the class of algebras isomorphic to  direct  products  of algebras in \(K\)). (The proofs of forms [0 U] and [0 V] in ZF depend on the axiom of regularity.)

 

Howard-Rubin number: 0 V

Citations (articles): Andreka/Nemeti [1980] Does \(SP K \supseteq PS K\) imply the axiom of choice?

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