Contracting for Information under Imperfect Commitment

Organizational theory suggests that authority should lie in the hands of those with information, yet the power to transfer authority is rarely absolute in practice. We investigate the validity and application of this advice in a model of optimal contracting between an uninformed principal and informed agent where the principal's commitment power is imperfect. We show that while full alignment of interests combined with delegation of authority is feasible, it is never optimal. The optimal contract is 'bang-bang'---in one region of the state space, full alignment takes place, in the other, no alignment takes place. We then compare these contracts to those in which the principal has full commitment power as well as to several 'informal' institutional arrangements.Imperfect commitment, optimal contracting, delegation

On the Benefits of Costly Voting

We study strategic voting in a Condorcet type model in which voters have identical preferences but differential information. Voters incur private costs of going to the polls and may abstain if they wish; hence voting is voluntary. We show that under majority rule with voluntary voting, it is an equilibrium to vote sincerely. Thus, in contrast to situations with compulsory voting, there is no conflict between strategic and sincere behavior. In large elections, the equilibrium is shown to be unique. Furthermore, participation rates are such that, in the limit, the correct candidate is elected with probability one. Finally, we show that in large elections, voluntary voting is welfare superior to compulsory voting.

Linearizable Replicated State Machines With Lattice Agreement

This paper studies the lattice agreement problem in asynchronous systems and explores its application to building a linearizable replicated state machine (RSM). First, we propose an algorithm to solve the lattice agreement problem in O(log f) asynchronous rounds, where f is the number of crash failures that the system can tolerate. This is an exponential improvement over the previous best upper bound of O(f). Second, Faleiro et al have shown in [Faleiro et al. PODC, 2012] that combination of conflict-free data types and lattice agreement protocols can be applied to implement a linearizable RSM. They give a Paxos style lattice agreement protocol, which can be adapted to implement a linearizable RSM and guarantee that a command by a client can be learned in at most O(n) message delays, where n is the number of proposers. Later, Xiong et al in [Xiong et al. DISC, 2018] gave a lattice agreement protocol which improves the O(n) message delay guarantee to O(f). However, neither of the protocols is practical for building a linearizable RSM. Thus, in the second part of the paper, we first give an improved protocol based on the one proposed by Xiong et al. Then, we implement a simple linearizable RSM using our improved protocol and compare our implementation with an open source Java implementation of Paxos. Results show that better performance can be obtained by using lattice agreement based protocols to implement a linearizable RSM compared to traditional consensus based protocols

Linear Logic for Meaning Assembly

Semantic theories of natural language associate meanings with utterances by providing meanings for lexical items and rules for determining the meaning of larger units given the meanings of their parts. Meanings are often assumed to combine via function application, which works well when constituent structure trees are used to guide semantic composition. However, we believe that the functional structure of Lexical-Functional Grammar is best used to provide the syntactic information necessary for constraining derivations of meaning in a cross-linguistically uniform format. It has been difficult, however, to reconcile this approach with the combination of meanings by function application. In contrast to compositional approaches, we present a deductive approach to assembling meanings, based on reasoning with constraints, which meshes well with the unordered nature of information in the functional structure. Our use of linear logic as a `glue' for assembling meanings allows for a coherent treatment of the LFG requirements of completeness and coherence as well as of modification and quantification.Comment: 19 pages, uses lingmacros.sty, fullname.sty, tree-dvips.sty, latexsym.sty, requires the new version of Late

The Design Of Functional Supramolecular Gels And Coatings Using Hydrophobically Modified Biopolymers And Polypeptoids

Our recent work is based on the hydrophobic modification of biopolymers to provide building blocks for supramolecular architectures. The attachment of long chain alkyl groups to the polymer backbone allows the polymer to stick to hydrophobic surfaces and to “hook” onto lipid bilayers. The hydrophobic effect exhibited by such systems can be used to design new functional nanostructures. For example, the use of such polymers to capture and tether liposomes leads to surfaces with densely packed liposomal layers that exhibit very low coefficients of friction in sliding lubrication, representative of articular joints. We also extend this concept to a system of hydrophobically modified polypeptoids (HMPs) which are amphiphilic pseudo-peptidic macromolecules with hydrophobic groups attached randomly along the polypeptoid backbone. We show that these biocompatible polymers connect across lipid bilayers and thus form layered structures on liposomes. The transition from a single bilayer to multiple bilayer structures is characterized by small angle neutron scattering (SANS) and cryo-transmission electron microscopy (cryo-TEM). Of specific interest is the observation that small bilayer rafts reattach to fresh unilamellar liposomes and self-assemble to form new two-bilayered liposomes reminiscent of two-bilayered organelles such as the nucleus in eukaryotic cells. These observations have significance to designing new nanoscale drug delivery carriers. Results on the in-vitro delivery of a highly hydrophobic chemotherapeutic agent, sorafenib, to hepatocellular carcinoma cells shows the feasibility of the concept