a totally minimal RDFa doc, please

Can someone write me a totally minimal piece of XHTML_RDFa document, with
nothing in it except an RSA pubkey and a cert:id binding, and whatever
namespaces and foaf profile types necessary.

 

Henry's mywxiki stuff is good at RDFa, and works with uriburner queries
(more to the point). But, my profile page there is choc full of wiki stuff
that just confuses -  and Ive failed 4 times now to reduce to  a minimum so
I can host my own HTML homepage, with my own generated keypair. I just want
the guts, that matters (and for uriburner to be still be happy that its
valid RDFa).