3 http://hdl.handle.net/10338.dmlcz/116907 3 Hyperarchimedische Teilbarkeitshalbgruppen http://hdl.handle.net/10338.dmlcz/102325 Hyperarchimedische Teilbarkeitshalbgruppen On $\alpha$-ideals and generalized $\alpha$-ideals in semigroups http://hdl.handle.net/10338.dmlcz/102324 On $\alpha$-ideals and generalized $\alpha$-ideals in semigroups Smoothness as an invariant property of coefficients of linear differential equations http://hdl.handle.net/10338.dmlcz/102323 Smoothness as an invariant property of coefficients of linear differential equations On the lattice of convex subsets of a partial monounary algebra http://hdl.handle.net/10338.dmlcz/102322 On the lattice of convex subsets of a partial monounary algebra