|   | 1 |  initial version  | 
You can always use a Python def:
sage: def f(v):
    return v.dot_product(vector((1,1)))
sage: f(vector((2,1)))
3
 Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.
 
                
                Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.