The sign of m^13 ⋅ n^5 depends on the signs of the variables m and n.
If both m and n are positive, then m^13 is positive, n^5 is positive, and their product is positive.
If both m and n are negative, then m^13 is negative (an odd power of a negative number is negative), n^5 is negative (an odd power of a negative number is negative), and their product is positive (a negative multiplied by a negative is positive).
If one of m or n is negative and the other is positive, then m^13 is negative (an odd power of a negative number is negative), n^5 is positive (an odd power of a positive number is positive), and their product is negative (a negative multiplied by a positive is negative).
Therefore, we cannot determine the sign of m^13 ⋅ n^5 without additional information about the signs of m and n.