{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2024,9,6]],"date-time":"2024-09-06T03:48:54Z","timestamp":1725594534329},"publisher-location":"Vienna","reference-count":3,"publisher":"Springer Vienna","isbn-type":[{"type":"print","value":"9783211829714"},{"type":"electronic","value":"9783709165102"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[1997]]},"DOI":"10.1007\/978-3-7091-6510-2_3","type":"book-chapter","created":{"date-parts":[[2011,7,4]],"date-time":"2011-07-04T11:31:40Z","timestamp":1309779100000},"page":"39-53","source":"Crossref","is-referenced-by-count":25,"title":["Heterogeneous Relation Algebra"],"prefix":"10.1007","author":[{"given":"Gunther","family":"Schmidt","sequence":"first","affiliation":[]},{"given":"Claudia","family":"Hattensperger","sequence":"additional","affiliation":[]},{"given":"Michael","family":"Winter","sequence":"additional","affiliation":[]}],"member":"297","reference":[{"key":"3_CR1","unstructured":"To avoid set-theoretic problems we restrict ourselves to categories where every class of mor-phisms MorR [A, B] is a set. Such categories are called locally small."},{"key":"3_CR2","unstructured":"Recall that in Chapt. 1 the small circle was used for composition of morphisms in preference to the semicolon. Here, however, we wish to emphasize that morphisms are to be thought of as relations, therefore we revert to the semicolon."},{"key":"3_CR3","unstructured":"The universal covering got its name from a similar concept in the theory of Riemann surfaces."}],"container-title":["Relational Methods in Computer Science"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/link.springer.com\/content\/pdf\/10.1007\/978-3-7091-6510-2_3.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2020,11,23]],"date-time":"2020-11-23T09:45:28Z","timestamp":1606124728000},"score":1,"resource":{"primary":{"URL":"http:\/\/link.springer.com\/10.1007\/978-3-7091-6510-2_3"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1997]]},"ISBN":["9783211829714","9783709165102"],"references-count":3,"URL":"https:\/\/doi.org\/10.1007\/978-3-7091-6510-2_3","relation":{},"subject":[],"published":{"date-parts":[[1997]]}}}