[EM] Later no harm, Condorcet, and randomization

[Jobst Heitzig]

Dear Kevin!

you wrote:
> By the way, I think Later-no-harm is very important, in order to coax
>  information out of the voters, and avoid de facto Clone-Winner
> failures.

I agree with the first, that's why I try to find a compromise between
LNH and Condorcet.

But what do you mean by "de facto Clone-Winner failures"?

> I'm still digesting your suggestion. I believe Later-no-harm is
> normally stricter than this, though: No candidate ranked above the
> new preference is allowed to suffer a decrease in the probability of
> being elected, even if that probability moves upwards in the voter's
> ranking.

Yes, Woodall's definition for the non-deterministic case is different. I
was only saying that for deterministic situations both agree!

> But I don't think loosening this criterion would help much, since
> normally if adding a preference can affect other candidates' odds of
> election, you don't know whether these candidates are ranked above or
> below the new preference.

Sorry, I don't understand this one... Anyway, I think my loosening of
LNH is indeed of help: It is consistent with Condorcet, whereas LNH is not.

> A Condorcet winner always makes it into the CDTT set, incidentally. I
>  think that's good enough for me.

If I understand CDTT right, it is equal to the Smith set, at least when
no pairwise ties occurr, am I right? So what you suggested a few posts
earlier was to use "Random Ballot on the Smith Set", right? Well, I
think that would be more randomization than needed. I would prefer to
restrict the choice to uncovered candidates, by using one of the Chain
Climbing methods from yesterday, for example. What do you think about them?

Yours, Jobst