[EM] Truncation

[Forest Simmons]

Suppose that somebody comes up with a great method that requires complete
rankings, perhaps a de-cloned version of the Kemeny Order.

Here's a suggestion for a convention on filling in the truncated ballots:

Automatically rank the truncated candidates according to the candidate
card published by the highest ranked candidate on the ballot.

So if a ballot comes in as A>B>C=D, and candidate A's published preference
order is A>D>C>B, then the ballot is completed as A>B>D>C.

A more complicated example:

Let's say a ballot comes in as A=B>C=D, and the published preferences of
candidates A and B are A>B>C>D and B>A>C>D, respectively.

Then it is clear that C=D should be replaced with C>D, but how about the
A=B?

We consult C's published preference order C>B>A>D, to break the tie.

The result is B>A>C>D.