American mathematical physicist who made fundamental contributions to superstring theory. |
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
A city of west-central Germany on the Ruhr River east-southeast of Essen. Chartered in 1825, it is an industrial center. |
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.