[EM] Banks//Approval fulfils INI/ICI

[Markus Schulze]

Hallo,

the problem with the Banks set is: By ranking the Banks winner A
higher it is possible that another candidate D who was not a Banks
winner before becomes a Banks winner. Therefore, single-winner
election methods that restrict their considerations to the Banks
set usually violate monotonicity.

Example:

  A>B,B>C,C>D,D>A,B>D,C>A. Here, the Banks set is A,B,C.

  Suppose some voters rank candidate A higher so that "C>A"
  is replaced by "A>C". Now, the Banks set is A,B,D. Thus,
  by ranking candidate A higher candidate D becomes a Banks
  winner.

Markus Schulze