xsd select multiple values from enumeration or equivalent type

Question

I have the following XSD sample

Answer 1

If you can loose the comma (not supported as a separator in XSD), and be content with whitespaces, then this is your solution:

You're basically using a list, therefore something like this would be perfectly valid:

Monday Tuesday Wednesday 

To be proactive here... if, for example, one might want to ensure uniqueness of the values, then this cannot be enforced in XSD.