What We Are Reading Today: Crossing the Pomerium by Michael Koortbojian

Short Url
Updated 23 January 2020

What We Are Reading Today: Crossing the Pomerium by Michael Koortbojian

The ancient Romans famously distinguished between civic life in Rome and military matters outside the city — a division marked by the pomerium, an abstract religious and legal boundary that was central to the myth of the city’s foundation. 

Michael Koortbojian explores how the Romans used social practices and public monuments to assert their capital’s distinction from its growing empire, to delimit the proper realms of religion and law from those of war and conquest, and to establish and disseminate so many fundamental Roman institutions across three centuries of imperial rule. Crossing the Pomerium probes such topics as the appearance in the city of Romans in armor, whether in representation or in life, the role of religious rites on the battlefield, and the military image of Constantine on the arch built in his name. 

The book reveals how, in these instances and others, the ancient ideology of crossing the pomerium reflects the efforts of Romans not only to live up to the ideals they had inherited, but also to reconceive their past and to validate contemporary practices during a time when Rome enjoyed growing dominance in the Mediterranean world.


What We Are Reading Today: Introductory Lectures on Equivariant Cohomology

Updated 31 March 2020

What We Are Reading Today: Introductory Lectures on Equivariant Cohomology

Author: Loring W. Tu

This book gives a clear introductory account of equivariant cohomology, a central topic in algebraic topology.
Equivariant cohomology is concerned with the algebraic topology of spaces with a group action, or in other words, with symmetries of spaces. First defined in the 1950s, it has been introduced into K-theory and algebraic geometry, but it is in algebraic topology that the concepts are the most transparent and the proofs are the simplest. One of the most useful applications of equivariant cohomology is the equivariant localization theorem of Atiyah-Bott and Berline-Vergne, which converts the integral of an equivariant differential form into a finite sum over the fixed point set of the group action, providing a powerful tool for computing integrals over a manifold. Because integrals and symmetries are ubiquitous, equivariant cohomology has found applications in diverse areas of mathematics and physics.
Assuming readers have taken one semester of manifold theory and a year of algebraic topology, Loring Tu begins with the topological construction of equivariant cohomology.