Full Idea
One type of generalisation in mathematics extends a system to go beyond what is was originally set up for; another kind involves abstracting away from some details in order to capture similarities between different systems.
Gist of Idea
Mathematical generalisation is by extending a system, or by abstracting away from it
Source
Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 5.2.2)
Book Reference
Colyvan,Mark: 'An Introduction to the Philosophy of Mathematics' [CUP 2012], p.87