My research interests include Mechanism design, Cost sharing, Game theory, Social choice theory and Microeconomic theory.

Job
market paper

“Secure
Implementation in Production Economies” (pdf)

**Abstract:**
One thing that has been assumed for a long time is that whenever there
is dominant strategy equilibrium in the game form of any mechanism and the
outcome corresponding to that strategy profile is socially optimal, people will
play that particular equilibrium strategy profile. The theory has been silent
on why they will play that particular strategy profile when there are other
(Nash) equilibria. The Nash/Bayes’ Nash implementation being a possible
solution to this problem suffers from the drawback of either the requirement of
the designer knowing the (common) prior (in case of Bayes’ Nash
implementation) or the requirement of the players predicting the actions of
other players and collaborate without pre-talk (in case of Nash implementation
with absence of dominant strategy or unique Nash).

Secure implementation [Saijo et al. (2007)] is a relatively new concept
in the theory of mechanism design and implementation. This requires double
implementation in Dominant Strategy Equilibrium and Nash Equilibrium by the
same Mechanism. This concept has worked well in some particular environments
and has been tested on data [Cason et al. (2006)]. Unsurprisingly, being
stronger than both the two above said concepts of implementation, there are
many impossibility results in specific environments with richer domains. We
look for secure implementability in production economies with divisible goods.
We find that a very broad generalization of "Serial" Social Choice
Function (SCF) [Moulin and Shenker (92)] as defined in [Shenker (92)] is
securely implementable. We call such functions as Generalized Serial SCF (GSS).
We also find that under certain conditions the Fixed Path SCFs are special
cases of GSS and thus they are also securely Implementable. We conjecture that these are the only
securely implementable SCFs in our environment if we add few desirable axioms.

Working
paper

“Implementing Efficient Graphs
in Connection Networks” (pdf) co-authored with Ruben
Juarez

**Abstract:** We consider the problem of sharing
the cost of a network which meets the connection demands of a set of agents.
The agents simultaneously choose a path in the network connecting the demand
nodes of the agents, and a mechanism splits the total cost of the network
formed among the participants.

The recent literature has
converged to the *Shapley mechanism* (Sh) which splits the cost of edges
equally among its users. Two reasons motivate us to look at alternatives
mechanisms. First, Sh is inefficient, asymmetric and discontinuous at
equilibrium. Second, Sh requires an amount of information which may not be
practical in many settings.

We characterize a class of
mechanisms in a setting of minimal information requirement, specifically when
the inputs of a mechanism are the total cost of the network formed and the cost
of the paths demanded by the agents. The Average Cost mechanism (AC) and other
asymmetric mechanisms implement the efficient connection. These mechanisms are
characterized under three alternative robust properties
of efficient implementation.

We also show that efficiency
and individual rationality are mutually incompatible. The Egalitarian mechanism
(EG), a variation of AC that meets individual rationality, is an optimal mechanism
(under the price of stability measure) across all individually rational
mechanisms. EG outperforms Sh on the grounds of information requirements,
stability and symmetry at equilibrium. Moreover, EG is no more inefficient than
Sh.

Publications:

**Book:**

SMALL AREA ESTIMATES OF
SELECTED WELFARE INDICATORS: RESULTS FOR UTTARANCHAL. November 2005,
United Nations World Food Programme. Co-authored with
Shubhashis Gangopadhayay, PAN Network, Maithili
Ramachandran, T.O.Sridevi, Brinda Viswanathan and Wilima Wadhwa.