Vol. 2, No. 3, 2020

Download this article
Download this article For screen
For printing
Recent Issues
Volume 6, Issue 1
Volume 5, Issue 4
Volume 5, Issue 3
Volume 5, Issue 2
Volume 5, Issue 1
Volume 4, Issue 4
Volume 4, Issue 3
Volume 4, Issue 2
Volume 4, Issue 1
Volume 3, Issue 4
Volume 3, Issue 3
Volume 3, Issue 2
Volume 3, Issue 1
Volume 2, Issue 4
Volume 2, Issue 3
Volume 2, Issue 2
Volume 2, Issue 1
Volume 1, Issue 4
Volume 1, Issue 3
Volume 1, Issue 2
Volume 1, Issue 1
The Journal
About the journal
Ethics and policies
Peer-review process
Statement, 2023
 
Submission guidelines
Submission form
Editorial board
 
Subscriptions
 
ISSN (electronic): 2576-7666
ISSN (print): 2576-7658
Author index
To appear
 
Other MSP Journals
This article is available for purchase or by subscription. See below.
Monodromy and log geometry

Piotr Achinger and Arthur Ogus

Vol. 2 (2020), No. 3, 455–534
Abstract

A now classical construction due to Kato and Nakayama attaches a topological space (the “Betti realization”) to a log scheme over . We show that in the case of a log smooth degeneration over the standard log disc, this construction allows one to recover the topology of the germ of the family from the log special fiber alone. We go on to give combinatorial formulas for the monodromy and the d2 differentials acting on the nearby cycle complex in terms of the log structures. We also provide variants of these results for the Kummer étale topology. In the case of curves, these data are essentially equivalent to those encoded by the dual graph of a semistable degeneration, including the monodromy pairing and the Picard–Lefschetz formula.

PDF Access Denied

We have not been able to recognize your IP address 18.222.200.143 as that of a subscriber to this journal.
Online access to the content of recent issues is by subscription, or purchase of single articles.

Please contact your institution's librarian suggesting a subscription, for example by using our journal-recom­mendation form. Or, visit our subscription page for instructions on purchasing a subscription.

You may also contact us at contact@msp.org
or by using our contact form.

Or, you may purchase this single article for USD 40.00:

Keywords
log geometry, monodromy, degeneration, fibration
Mathematical Subject Classification 2010
Primary: 14D05, 14D06, 14F25
Milestones
Received: 7 February 2018
Revised: 30 May 2019
Accepted: 18 June 2019
Published: 9 October 2019
Authors
Piotr Achinger
Instytut Matematyezny PAN
Warsawa
Poland
Arthur Ogus
Department of Mathematics
University of California
Berkeley
United States