On 2-Homogeneity of Monounary Algebras
Danica Jakubı́ková-Studenovská · Czechoslovak Mathematical Journal · 2003
Fraïssé introduced the notion of a k-set-homogeneous relational structure. In the present paper the following classes of monounary algebras are described: $$S h_2 \left( S \right),S h_2 \left( {S^c } \right),S h_2 \left( {P^c } \right)$$ --the class of all algebras which are 2-set-homogeneous with respect to subalgebras, connected subalgebras, connected partial subalgebras, respectively, and $$H_2 \left( S \right),H_2 \left( {S^c } \right),H_2 \left( {S^c } \right)$$ --the class of all algebras which are 2-homogeneous with respect to subalgebras, connected subalgebras, connected partial subalgebras, respectively.