Formalizing Anonymity (2)

• Group Principals and Epistemic Logic (Syverson and Stubblebine):

• And group, Or group, Collective group,

• Threshold group: Action/knowledge of any subcollection of sufficient cardinality

  • Or group of collective groups bigger than threshold

• Example: (  k)-anonymity

• j (i)  ♦A( j (i1)) ∧… ∧ ♦A( j (ik))