Final answer:
CL(n,R) is the multiplicative group of invertible nxn matrices, R is the additive group of real numbers, and φ(A) = tr(A) with tr(A) being the sum of the diagonal elements of matrix A.
Step-by-step explanation:
Multiplicative Group and Additive Group:
CL(n,R) is the multiplicative group of invertible nxn matrices and R is the additive group of real numbers. In this context, the term 'group' refers to a set of elements with an operation that satisfies certain properties.
The Function φ:
The function φ maps the elements of CL(n,R) to real numbers by taking the trace (tr) of a matrix. 'tr(A)' represents the sum of the diagonal elements of matrix A.