The systematic research into and documentation of vernacular architecture, the beginnings of which could be observed no later than from the time of the preparations for the Czechoslavic Ethnographic Exhibition, developed fully at the beginning of the 1950s. The research followed older research and documentation works carried out by the Czechoslavic Ethnographic Society from its foundation in 1891, it included monographs devoted to selected locations/regions and evolved to a systematic ethnographic inventory during the first half of the 20th century. The architect Jiří Waage took part in the researches in 1953-1962.
Suppose G is a p-mixed splitting abelian group and R is a commutative unitary ring of zero characteristic such that the prime number p satisfies p ∈/ inv(R) ∪ zd(R). Then R(H) and R(G) are canonically isomorphic R-group algebras for any group H precisely when H and G are isomorphic groups. This statement strengthens results due to W. May published in J. Algebra (1976) and to W. Ullery published in Commun. Algebra (1986), Rocky Mt. J. Math. (1992) and Comment. Math. Univ. Carol. (1995).