{ "id": "1904.10420", "version": "v1", "published": "2019-04-23T16:55:59.000Z", "updated": "2019-04-23T16:55:59.000Z", "title": "Projection bands and atoms in pervasive pre-Riesz spaces", "authors": [ "Anke Kalauch", "Helena Malinowski" ], "categories": [ "math.FA" ], "abstract": "In vector lattices, the concept of a projection band is a basic tool. We deal with projection bands in the more general setting of an Archimedean pre-Riesz space $X$. We relate them to projection bands in a vector lattice cover $Y$ of $X$. If $X$ is pervasive, then a projection band in $X$ extends to a projection band in $Y$, whereas the restriction of a projection band $B$ in $Y$ is not a projection band in $X$, in general. We give conditions under which the restriction of $B$ is a projection band in $X$. We introduce atoms and discrete elements in $X$ and show that every atom is discrete. The converse implication is true, provided $X$ is pervasive. In this setting, we link atoms in $X$ to atoms in $Y$. If $X$ contains an atom $a>0$, we show that the principal band generated by $a$ is a projection band. Using atoms in a finite dimensional Archimedean pre-Riesz space $X$, we establish that $X$ is pervasive if and only if it is a vector lattice.", "revisions": [ { "version": "v1", "updated": "2019-04-23T16:55:59.000Z" } ], "analyses": { "subjects": [ "46A40", "06F20", "47B65" ], "keywords": [ "projection band", "pervasive pre-riesz spaces", "finite dimensional archimedean pre-riesz space", "vector lattice cover", "converse implication" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }