Hi Ernest:
Thank you for you answers. I had read Ajax documentation. I am using index table engine search. I am familiar with Ajax’s keyword logic system. AND, the default, is most appropriate. Results relevancy in search results is not quite what it should be using Ajax (nor WP search either). I can only suppose that is the best you can do.
You did not answer my question regarding a blank search giving spurious results rather than null results. Perhaps you will fix this anomaly in a future release.
Best regards,
Ishi Nobu