Converses
Revision as of 16:12, 30 May 2009 by Volker gast (talk | contribs) (Created page with 'Two predicates are '''converses''' iff they describe the same relation from opposing perspectives. :For any pair of predicates ''P'', ''Q''<br>''P'' and ''Q'' are converses iff ...')
Two predicates are converses iff they describe the same relation from opposing perspectives.
- For any pair of predicates P, Q
P and Q are converses iff- for all x, y,
- P(x,y) ↔ Q(y,x)
- for all x, y,
Examples
- 'above' vs. 'below'
- 'in front of' vs. 'behind'
- 'before' vs. 'after'
- 'parent of' vs. 'child of'
- 'huest' vs. 'host'
