A similar notion (at least in spirit) was introduced by Simon Henry in An abstract elementary class non-axiomatizable in $L_{(\infty,\kappa)}$, see Def. 4.2 and later used by Michael Lieberman, Jiří Rosický, Sebastien Vasey in Hilbert spaces and C∗-algebras are not finitely concrete.

A similar notion (at least in spirit) was introduced by Simon Henry in An abstract elementary class non-axiomatizable in $L_{(\infty,\kappa)}$, see Def. 4.2 and later used by Michael Lieberman, Jiří Rosický, Sebastien Vasey in Hilbert spaces and $C^∗$-algebras are not finitely concrete.

A similar (equivalent?) notion was introduced by Simon Henry in An abstract elementary class non-axiomatizable in $L_{(\infty,\kappa)}$, see Def. 4.2 and later used by Michael Lieberman, Jiří Rosický, Sebastien Vasey in Hilbert spaces and C∗-algebras are not finitely concrete.

A similar notion (at least in spirit) was introduced by Simon Henry in An abstract elementary class non-axiomatizable in $L_{(\infty,\kappa)}$, see Def. 4.2 and later used by Michael Lieberman, Jiří Rosický, Sebastien Vasey in Hilbert spaces and C∗-algebras are not finitely concrete.