olid coalitions For every election E = (C, V ) and each k ∈[ C ],ifatleast V k voters rank some candidate c first then c belongs to every committee in R(E, k). Consensus committee For every election E = (C, V ) and each k ∈[ C ], if there is a k-element set W , W ⊆ C, such that each voter ranks some member of W first and each member of W is ranked first by either V k or V k voters then R(E, k) ={W }. Unanimity For every election E = (C, V ) and each k ∈[ C ], if each voter ranks the same k candidates W on top (possibly in different order), then R(E, k) ={W } (strong unanimity) or W ∈ R(E, k) (weak unanimity)