[EM] Juho,5/25/12, roughly 2230 UT

Thu May 24 14:17:29 PDT 2012

From: election-methods-bounces at lists.electorama.com
[mailto:election-methods-bounces at lists.electorama.com] On Behalf Of Juho
Laatu
Sent: Thursday, May 24, 2012 5:18 AM
To: em Methods
Subject: Re: [EM] Juho,5/25/12, roughly 2230 UT

On 24.5.2012, at 5.40, Michael Ossipoff wrote:

Juho says:

Some further definitions are however needed. What is the definition of and
how will the voters determine if the election is a u/a election?

[endquote]

I'd replied:

An election is, for you, u/a if, for you, the candidates can be divided into
two sets such that the merit differences within each set are negligible in
comparison to the merit difference between the sets.

Juho says:

Good, we are making progress. Term "u/a" now has a definition 

[endquote]

I first posted that definition months ago, Juho :-)

I've posted it very many times during the past month.

Juho says:

"if, for you, the candidates can be divided into two sets such that the
merit differences within each set are negligible in comparison to the merit
difference between the sets". Terms "acceptable" and "unacceptable" refer to
this definition of "u/a".

[endquote]

Juho catches on fast.

Juho says:

Also terms "compromise"

[endquote]

I refer Juho to a dictionary, if he wants to find out what "compromise"
means.

It seems to be just a chosen name for the "only acceptable who can beat the
unacceptables".

[endquote]

That's what I had just said. 

Juho says:

It seems that the strategy has a condition that there must be exactly one
acceptable candidate that is also a potential winner (for he precondition
for the use of the strategy to be true).

[endquote]

Wrong. There need only be one or more possibly-winnable candidates in each
of the two sets, in order for it to satisfy my definition of u/a.

You're confusing the u/a definition with the conditions under which
favorite-burial can be optimal in Condorcet.

As I've been saying, of the two sets referred to in the above-stated
definition, the "acceptable set" is the one that the voter in question
prefers to the other set. That other set is the "unacceptable set". An
acceptable candidate is a candidate in the acceptable set. An unacceptable
candidate is a candidate in the unacceptable set.

We seem to have the same definition.

[endquote]

:-)  That's because you've finally caught on to what my definition is. Very
good, though it took you a long time, and those definitions were posted long
ago.

he's taken on a new tactic, one of asking for definitions

The reason why I (systematically) request exact and directly implementable
definitions

[endquote]

You're requesting definitions that I've already posted. In some cases
they're definitions that I've posted very many time. In some cases, they're
definitions that I've been posting for months.

You're also sometimes requesting definitions of words and expressions that I
use in the standard manner, with the obvious standard dictionary meaning.

You might just as well demand the definition of "the", etc.

Juho says:

is that in order to have a strategy that would work in real life elections
we must have a definition that we can print in the newspapers and then
expect regular voters to follow. 

[endquote]

Ok, now we're talking about strategy instructions or suggestions.

But Juho wants to criticize my strategy suggestions because he still doesn't
understand them. I suggest that Juho isn't typical in that regard. Most
anyone would understand my strategy suggestions.

Juho says:

(An alternative would be to have a strategy that we can send to the parties
and other interest groups, and based on that description those groups could
then publicly recommend how the voters should modify their vote, or what
kind of a vote to cast.)

[endquote]

That would work, but Approval strategy isn't difficult enough to require
that.

Then back to the strategy.

An alternative definition of the strategy could be "If, for you, the
candidates can be divided into two sets ("acceptables" and "unacceptables")
such that the merit differences within each set are negligible in comparison
to the merit difference between the sets, and there is exactly one
acceptable candidate that can win all the unacceptable candidates, then you
should rank that acceptable candidate first and then rank all the other
candidates in your sincere preference order".

[endquote]

Your "alternative definition" is the same as the definition that I'd been
giving, except for the sincere preference order of the other acceptables.
I'd merely spoken of the need to rank Compromise alone in 1st place. I don't
necessarily agree about the "sincere preference order" for the other
acceptables. If they can't win, why would it make any difference. If they
have some small chance of winning, then it would seem best to rank them in
order of what winnability they have.

And it really maybe needn't be that Compromise is the only candidate that
can beat Worst. I said it that way for simplicity. It's probably enough that
Compromise has a better chance than the other acceptables. I haven't given
consideration to that, because I've preferred the simpler case in which
Compromise is the only candidate who can beat Worse.

Later I said that it needn't be u/a. The important thing is that Compromise
is the only candidate who can beat Worse.

Juho says:

For example a voter with sincere opinon a > B > c >>> d > e should vote B >
a > c > d > e. The uppercase letter refers to the candidate that, according
to the voter, can win all the unacceptable candidates. The strategy does not
take position on if there are potential winners among the unacceptable
candidates.

[endquote]

Favorite-burial only makes any sense if Worse, or the unacceptable, is/are
winnable.

Btw, the conditions of the strategy could maybe be also a bit more relaxed
with respect to candidates than the voter expects not to win in any case
falling exactly in the "acceptable" and "unacceptable" categories. I mean
that maybe it is enough if all the other potential winners are unacceptable,
for the strategy to take effect. But this is a minor topic that we can skip
for now. Also the case where there are no unacceptable potential winners
could be slightly different.

As I was saying, I now don't say that u/a is necessary for the optimality of
favorite-burial in Condorcet.

The strategy says that if the top favourites of the voter are candidates
that can not win, then they should be buried under the only acceptable
candidate that can win (the "Compromise") (if such a candidate exists). The
key strategic thought behind the strategy must be that by burying those
candidates as a precaution they can not be used to (or accidentally) bury
the only acceptable potential winner. 

[endquote]

They don't want to bury the only acceptable potential winner. They want to
rank hir alone at top.

If so, then this is a defensive startegy whose idea is to respond to another
offensive strategy used by others (or maybe as a very marginal case, a
response to an unintentional loop).

[endquote]

Yes, there needn't be any assumption about offensive strategy.

Juho says:

The strategy that this strategy responses to could be either rational or
irrational. 

[endquote]

Condorcet's favorite-burial strategy needn't be responding to any other
strategy.

Juho says:

I assume that the strategy applies at least to all typical winning votes
based Condorcet methods.

Am I on the correct track so far?

[endauote]

Yes, I'd say that, under the conditions I described, favorite-burial is
optimal in all Condorcet(wv) versions. But the sometime optimality of
favorite-burial is, by definition, a property of all FBC-failing methods.
I'm not trying to single-out Condorcet(wv). It's just one of many
FBC-failing methods.

Mike Ossipoff

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