| Title: | Orthomodular lattices that are  horizontal sums of Boolean algebras (English) | 
| Author: | Chajda, Ivan | 
| Author: | Länger, Helmut | 
| Language: | English | 
| Journal: | Commentationes Mathematicae Universitatis Carolinae | 
| ISSN: | 0010-2628 (print) | 
| ISSN: | 1213-7243 (online) | 
| Volume: | 61 | 
| Issue: | 1 | 
| Year: | 2020 | 
| Pages: | 11-20 | 
| Summary lang: | English | 
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| Category: | math | 
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| Summary: | The paper deals with orthomodular lattices which are so-called horizontal sums of Boolean algebras. It is elementary that every such orthomodular lattice is simple and its blocks are just these Boolean algebras. Hence, the commutativity relation plays a key role and enables us to classify these orthomodular lattices. Moreover, this relation is closely related to the binary commutator which is a term function. Using the class $\mathcal H$ of horizontal sums of Boolean algebras, we establish an identity which is satisfied in the variety generated by $\mathcal H$ but not in the variety of all orthomodular lattices. The concept of ternary discriminator can be generalized for the class $\mathcal H$ in a modified version. Finally, we present several results on varieties generated by finite subsets of finite members of $\mathcal H$. (English) | 
| Keyword: | orthomodular lattice | 
| Keyword: | horizontal sum | 
| Keyword: | commuting elements | 
| Keyword: | Boolean algebra | 
| MSC: | 06C15 | 
| MSC: | 06C20 | 
| MSC: | 06E75 | 
| idZBL: | Zbl 07217154 | 
| idMR: | MR4093425 | 
| DOI: | 10.14712/1213-7243.2020.003 | 
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| Date available: | 2020-04-30T11:12:19Z | 
| Last updated: | 2022-04-04 | 
| Stable URL: | http://hdl.handle.net/10338.dmlcz/148071 | 
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