https://medium.com/question-time/ask-dr-silverman-10-mathematical-objects-number-ology-not-numerology-82fcf0492528

Mathematicians don’t much think about types of mathematical objects. A mathematical object can be anything that mathematicians work on, including functions, sets, vectors, numbers, points, lines, circles, ellipses, matrices, infinite series, and so on. The various specialties of mathematics, like linear algebra, abstract algebra, topology, real analysis, complex analysis, geometry, combinatorics, and many more, can be organized by the type of mathematical objects they primarily concentrate on. Different areas of mathematics have some objects in common. For instance, most mathematical areas deal with objects like numbers, functions, and sets.

Mathematicians don’t much think about types of mathematical objects. A mathematical object can be anything that mathematicians work on, including functions, sets, vectors, numbers, points, lines, circles, ellipses, matrices, infinite series, and so on. The various specialties of mathematics, like linear algebra, abstract algebra, topology, real analysis, complex analysis, geometry, combinatorics, and many more, can be organized by the type of mathematical objects they primarily concentrate on. Different areas of mathematics have some objects in common. For instance, most mathematical areas deal with objects like numbers, functions, and sets.