Three Brief Proofs of Arrow's Impossibility Theorem by John Geanakoplos.
Week III We defined social choice functions and proved the Gibbard-Satterthwaite theorem. We followed the presentation in
Arrow's Theorem and the Gibbard-Satterthwaite Theorem: A Unified Approach by Philip Reny
Week IV: The Shapley Shubik power index and information aggregation
We described the model of cooperative $n$ persons game and the Shapley value. We described the axiomatic definition of the value as well as the formulas of Shapley and of Owen. We stated the connection of Shapley-Shubik power index with information aggregation.
A good source is The Shapley Value by Eyal Winter.
The results on aggregation of information and on indeterminacy (next week) are from Social indeterminacy, by Gil Kalai.
Week V: Indeterminacy.