We've been discussing four added-ballot monotonicity criteria: Listing them in order of worst ones (to fail) first:
Mono-Add-Plump Mono-Add-Solo-Top Mono-Add-Top Participation Woodall describes more than that, including some "append" criteria dealing with bottom-end changes, which I don't consider as important. I didn't find Mono-Add-Solo-Top in Woodall's paper, though maybe you will. I'm continuing to use that name for it here, because it fits in well with Woodall's naming. It's of interest to compare some methods with regard to the four above-listed criteria. In the table below, the methods are on the left, and the criteria are on the right. A method fails a criterion if it is separated from it by a horizontal line that is below the method: TUC, ICT, MJ.....| Mono-Add-Plump ------------------------------------------------ IRV.....................| Mono-Add-Solo-Top --------------------------------------------------- ...........................| Mono-Add-Top Approval, Score.| Participation Note that TUC fails, but Approval passes, Mono-Add-Solo-Top, which could be called "Make-Your-Favorite-Lose" Now, someone could argue that IRV fails Mono-Raise. Mono-Raise and Partilcipation are exact changed-ballot and added-ballot counterparts to eachother. Someone could say, "IRV fails that changed ballot criterion and some added-ballot criteriia, while TUC only fails added-ballot criteria." But, for one thing, TUC fails more added-ballot criteria. For anotother thing, based on the paragraph before this one, the criteria that TUC fails are worse than the ones that IRV fails. Mike Ossipoff ---- Election-Methods mailing list - see http://electorama.com/em for list info