from Part II - What is New in Set Theory
Published online by Cambridge University Press: 28 September 2020
The last sections of Chapter 17 show why the forcing techniques that we have at N1 cannot possibly work at singular cardinals. Similar concerns apply to the successors of singular cardinals. For example, if we wish to study values of various cardinal invariants at κ, then we had better make sure that they are not trivially equal to κ+. Therefore we wish to work in the context of 2κ > κ+. If, in addition, we have that κ is a strong limit cardinal, then we are automatically dealing with the failure of SCH and so with large cardinals. In this situation, the cardinal invariants at κ+ are also affected. This situation presents many challenges and at this moment there is no unique technique or an axiom that deals with it. However, some techniques have emerged in recent years, two of which will be described below.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.