Hi

We discovered an unexpected search behaviour in our archive (Organic Eprints at http://orgprints.org). Searches that include multiple (two or more) items in both of two subject trees do not give a match (see, e.g., http://orgprints.org/id/saved_search/1644), though there should be many eprints that match, whereas searches that retain just one item in one of the two trees do give a match (e.g., use the Refine search link in the Saved search linked to above and remove one of the items in one of the two subject trees). 

I found this unexpected search behaviour also in other ePrints archives, such as the Roar archive (see, e.g., http://roar.eprints.org/cgi/search/archive/advanced?_action_search=1&dataset=archive&exp=0%7C1%7C-recordcount%2F-date%7Carchive%7C-%7Cgeoname%3Ageoname%3AANY%3AEQ%3Ageoname_1_AS+geoname_1_EU%7Csoftware%3Asoftware%3AANY%3AEQ%3Aeprints+dspace%7C-%7Ceprint_status%3Aeprint_status%3AANY%3AEQ%3Aarchive&order=-recordcount%2F-date ) 

and the University of Glasgow archive (e.g., http://eprints.gla.ac.uk/cgi/search/advanced?screen=Search&documents_merge=ALL&documents=&title_merge=ALL&title=&creators_name_merge=ALL&creators_name=&abstract_merge=ALL&abstract=&date=&keywords_merge=ALL&keywords=&funding_funder_code_merge=ALL&funding_funder_code=&funding_funder_name_merge=ALL&funding_funder_name=&funding_project_name_merge=ALL&funding_project_name=&subjects=A&subjects=B&subjects_merge=ANY&divisions=10000000&divisions=20000000&divisions_merge=ANY&editors_name_merge=ALL&editors_name=&refereed=EITHER&publication_merge=ALL&publication=&journal_abbr_merge=ALL&journal_abbr=&issn_merge=ALL&issn=&issn_online_merge=ALL&issn_online=&id_number_merge=ALL&id_number=&creators_browse_id_merge=ALL&creators_browse_id=&satisfyall=ALL&order=-date%2Fcreators_name%2Ftitle&_action_search=Search ).  

But not in ePrints Soton (e.g., http://eprints.soton.ac.uk/cgi/search/archive/advanced?screen=Search&dataset=archive&documents_merge=ALL&documents=&eprintid=&title_merge=ALL&title=&contributors_name_merge=ALL&contributors_name=&abstract_merge=ALL&abstract=&date=&keywords_merge=ALL&keywords=&subjects=A&subjects=B&subjects_merge=ANY&divisions=uos2011-F1&divisions=uos2011-F4&divisions_merge=ANY&department_merge=ALL&department=&refereed=EITHER&publication%2Fseries_name_merge=ALL&publication%2Fseries_name=&documents.date_embargo=&shelves.shelfid=&satisfyall=ALL&order=contributors_name%2F-date%2Ftitle&_action_search=Search ).

The Organic Eprints archive runs ePrints version 3.3.15. I am not sure what version the other archives run on. I wanted to test the problem on the ePrints demo archive, but it seems to have been taken down.

Kind regards

Hugo