title: data structure to speed in-memory tagged object search on boolean function of tags?
body: <p>If I have a set of tags (&lt;100), and a set of objects (~25000), where each object has some sub-set of the tags, do you know of an existing data-structure that would allow for fast retrieval of those objects that satisfy some boolean function of the tags?</p>
  
  <p>Addition/deletion of tags and objects need not be particularly fast, but selection of those objects with tags that satisfy the boolean function should be.</p>
  
  <p>Now that I have written my question down, it looks as if I'm describing an in-memory database, but originally I was thinking of some binary tree like structure for the objects where, for each branch, taking the left/right branch would be equivalent to deciding on have/have-not some tag. But that would not allow don't-care tags? i am asking as I wondered if this has been done before and find it hard to google for data structures.</p>
  
  <ul>
  <li>Thanks in advance - Paddy.</li>
  </ul>