limit inverter subconditions to oracles

[diminator]

[ttmc]

I'm not sure "oracles" is the right way to characterize the kinds of inputs that can feed into inverters.

Signatures aren't good inputs because there's no way to verify that a signature is not available, only that one is available (and valid).

I guess the general principle is that both input states (true or false) must be verifiable. A timeout condition is like that: one can verify that it's now either before or after the cutoff time.

An oracle could be a source of random true/false values, for example.

Maybe only allow inputs that are "both-states-verifiable" or "dual-state-verifiable." Maybe there's a word for that.

[diminator]

will move to bdb extension of cc