Computable

Is the exponential function computable? Are union and intersection of closed subsets of the real plane computable? Are differentiation and integration computable operators? Is zero finding for complex polynomials computable? Is the Mandelbrot set decidable? And in case of computability, what is the computational complexity? Computable analysis supplies exact definitions for these and many other similar questions and tries to solve them.

This book is intended as an undergraduate senior level or beginning graduate level text for mathematical logic. There are virtually no prere­ quisites, although a familiarity with notions encountered in a beginning course in abstract algebra such as groups, rings, and fields will be useful in providing some motivation for the topics in Part III.

This book is for people who want to understand modern trade theory, particularly the Melitz model. It lays out Melitz theory from first principles and relates it to earlier theories of Armington and Krugman. For trade theory specialists, the book produces some significant conclusions. It identifies conditions under which Krugman and Melitz models produce essentially the same results for the welfare effects of trade liberalization as those obtained from Armington, and conditions under which this is not true. These findings will be of interest to academics and policy advisors who need to understand critiques of Armington by proponents of Krugman and Melitz.

This book is for people who want to understand modern trade theory, particularly the Melitz model. It lays out Melitz theory from first principles and relates it to earlier theories of Armington and Krugman. For trade theory specialists, the book produces some significant conclusions. It identifies conditions under which Krugman and Melitz models produce essentially the same results for the welfare effects of trade liberalization as those obtained from Armington, and conditions under which this is not true. These findings will be of interest to academics and policy advisors who need to understand critiques of Armington by proponents of Krugman and Melitz.