Relational Programming in miniKanren: Techniques, Applications, and Implementations

Thesis (Ph.D.) - Indiana University, Computer Sciences, 2009The promise of logic programming is that programs can be written relationally, without distinguishing between input and output arguments. Relational programs are remarkably flexible—for example, a relational type-inferencer also performs type checking and type inhabitation, while a relational theorem prover generates theorems as well as proofs and can even be used as a simple proof assistant. Unfortunately, writing relational programs is difficult, and requires many interesting and unusual tools and techniques. For example, a relational interpreter for a subset of Scheme might use nominal unification to support variable binding and scope, Constraint Logic Programming over Finite Domains (CLP(FD)) to implement relational arithmetic, and tabling to improve termination behavior. In this dissertation I present miniKanren, a family of languages specifically designed for relational programming, and which supports a variety of relational idioms and techniques. I show how miniKanren can be used to write interesting relational programs, including an extremely flexible lean tableau theorem prover and a novel constraint-free binary arithmetic system with strong termination guarantees. I also present interesting and practical techniques used to implement miniKanren, including a nominal unifier that uses triangular rather than idempotent substitutions and a novel “walk”-based algorithm for variable lookup in triangular substitutions. The result of this research is a family of languages that supports a variety of relational idioms and techniques, making it feasible and useful to write interesting programs as relations

Mathematics Yearbook 2021

The Deakin University Mathematics Yearbook publishes student reports and articles in all areas of mathematics with an aim of promoting interest and engagement in mathematics and celebrating student achievements. The 2021 edition includes 7 coursework articles, where students have extended upon submissions in their mathematics units, as well as 4 articles based on student research projects conducted throughout 2020 and 2021

The BG News May 3, 1979

The BGSU campus student newspaper May 3, 1979.https://scholarworks.bgsu.edu/bg-news/4616/thumbnail.jp

Debt overhang and sovereign debt restructuring

After the huge debt increases in the 1940s, due to the WWII, and in the 1980s due to the emerging markets’ debt crises, the debt overhang problem is once again at the center of the academic and political debate because of the recent debt crisis that affected the European countries in 2009. The debt overhang theory explains how an high level of debt distorts the optimal investment decisions and reduces government’s incentives, in the debtor country, to undertake the necessary "adjustment policies". A huge literature focuses on the negative effects deriving from a debt overhang condition. In particular, this kind of literature has been mostly used to describe and to study poor and less developed countries. Nowadays instead, the situation is quite different with the Greek case that represents a very peculiar and never experienced situation. Chapter 1 of the thesis starts with an introduction of the sovereign debt overhang problem. Then, since the aim is to study the possible policy interventions able to solve it, the focus is posed on sovereign debt restructuring as a resolution mechanism. A relief intervention can be considered, indeed, as a way to reduce the debt burden for a country struggling with an high level of debt. Descriptions of the restructuring process, of the macroeconomic consequences and of the Greek case are then provided in this chapter in addition to some stylised facts and an event analysis useful to communicate the main messages. In the past, several different strategies of debt restructuring have been implemented and the consequences they produced were often different case by case. It is then interesting to study the effectiveness of the several options that can be used to restructure public debt. For this reason, a very simple theoretical model is developed in Chapter 2 in order to study three different strategies that can be used to solve a sovereign debt overhang problem. In particular, two strategies are based on a debt restructuring process, via face value reduction or rescheduling, whereas a third one is based on conditional-additional official lending. This strategy relies on the idea that the debtor country can benefit of new lending from the official sector, in order to undertake a larger amount of investment. The aim of the model is to represent schematically the functioning of the three restructuring processes to gain insights into their differences and to study their consequences in term of incentives to invest in a "troubled country". An empirical evidence of the debt overhang hypothesis is then provided in Chapter 3. The combination of the sovereign debt crisis of 2009 and the fiscal consolidation policies implemented as a result, makes indeed interesting to study this hypothesis in Europe. The Chapter exploits then a panel dataset for the European countries, between 1995 and 2015, in order to examine the extent to which increased levels of public debt have led to reduced public investment. We start the analysis from basic POLS models and then we expand it gradually to FE, IV and GMM estimation models. The results validate the debt overhang hypothesis and remain robust across various model specifications

Mustang Daily, October 27, 2010

Student newspaper of California Polytechnic State University, San Luis Obispo, CA.https://digitalcommons.calpoly.edu/studentnewspaper/8106/thumbnail.jp

The BG News January 23, 2006

The BGSU campus student newspaper January 23, 2006. Volume 96 - Issue 84https://scholarworks.bgsu.edu/bg-news/8541/thumbnail.jp

The BG News October 16, 1997

The BGSU campus student newspaper October 16, 1997. Volume 80 - Issue 36https://scholarworks.bgsu.edu/bg-news/7226/thumbnail.jp