Published online by Cambridge University Press: 18 December 2009
Sobolev Spaces
Sobolev spaces are, roughly speaking, spaces of p-integrable functions whose derivatives are also p-integrable. There are two basic types of Sobolev spaces we wish to consider. In the first situation, we have a bounded domain Ω ⊂ ℝN and we consider functions u : Ω → ℝ for which u ≡ 0 on ∂Ω. In the second, we look at functions u : [0, T] → ℝN satisfying u(0) = u(T). The only problem in straightforwardly defining these spaces is that p-integrable functions need not be differentiate and restricting our attention to those that are differentiate does not provide us with what we want — the resulting spaces are not complete. We must weaken our notion of differentiability.
Definition A.1. In the following two cases we define an appropriate notion of weak differentiability.
To save this book to your Kindle, first ensure [email protected] 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.