Before revision:  }  Aronov, de Berg, Gudmundsson, and Horton [SoCG 2020] ,=\sup\{\beta\mid every finite multiset V in X admits a \beta-plurality point\}.
After revision:  } 1, this is equivalent to Condorcet winner, which rarely exists. The concept of \beta-plurality was suggested by Aronov, de Berg, Gudmundsson, and Horton [SoCG 2020] ,=\sup\{\beta\mid every finite multiset V in X admits a \beta-plurality point\}.