Full Idea
Mathematics is concerned with forms [eide]: its objects are not said of any underlying subject - for even if geometrical objects are said of some underlying subject, still it is not as being said of an underlying subject that they are studied.
Gist of Idea
Mathematics is concerned with forms, not with superficial properties
Source
Aristotle (Posterior Analytics [c.327 BCE], 79a08)
Book Reference
Aristotle: 'Posterior Analytics (2nd ed)', ed/tr. Barnes,Jonathan [OUP 1993], p.21
A Reaction
Since forms turn out to be essences, in 'Metaphysics', this indicates an essentialist view of mathematics.