2nd

2. A structure-preserving mapping between two mathematical structures
6. The branch of mathematics dealing with counting, arrangements, and combinations
8. Intersecting or lying at right angles; mathematically independent
10. A famous sequence where each number is the sum of the two preceding ones
12. The continuous analog of a sum, used to calculate areas under curves
13. An open, two-branched curve formed by the intersection of a plane with a cone
15. A mathematical object that generalizes scalars, vectors, and matrices
17. The instantaneous rate of change of a function with respect to one of its variables
18. A mathematical statement that appears to be true but has not yet been rigorously proved
20. The inverse mathematical operation to exponentiation

1. The study of geometric properties that are preserved under continuous deformations
3. A topological space that locally resembles Euclidean space near each point
4. A complex number system extending the complex numbers, often used in 3D rotations
5. A rectangular array of numbers or expressions arranged in rows and columns
7. A process or system that is randomly determined and has a random probability distribution
9. A real or complex number that is not the root of any integer polynomial, like Pi or e
11. An expression consisting of variables, coefficients, and non-negative integer exponents
14. A fundamental statement or proposition accepted as true without proof
16. A special scalar associated with a linear system of equations or matrix
19. A line that a curve approaches, as it heads towards infinity