TECH: Mark Shoulson waiting for a taxi

[Mr Andrew Rosta <ucleaar@UCL.AC.UK>]

If I remember right (probably not), a (long) while back Mark
wrote about waiting for a taxi - any taxi - to come along. Since
the taxi is non-specific, this rules out use of the le-series
- le karcrtaksi, lei karcrtaksi.
But "lo karcrtaksi" doesn't seem quite right, if it means
"there is some taxi such that M.S. was waiting for it" -
it suggests that a taxi for which Mark was not waiting could
have come along. And of course he wasn't waiting for every
taxi, either (or maybe he was?). My hazy recollection is that
Mark used "loi karcrtaksi" (the "loi" not the fukpi zei valsi)
- he was waiting for some manifestation of the mass of all X
such that X is a taxi.

If this works, it is useful for things like
  I want/seek a book (to prop open the door)
     mi sisku loi cukta
  I want/seek a book (a particular one I'm halfway through reading)
     mi sisku le cukta

Is this right? I know it was discussed earlier in the year by Iain
et al., but that discussion seems to have left scarcely any
trace in my memory.
-----------------
And