What is the name of shorting algorithm used? For example, Set X = { Apple = 1, Banana = 2, Cucumber = 3 } Set Y = { CFO = 1, CFO = 2, CSO = 3 } Combinations are in some order [X, Y] = K [1, 1] = 1 [1, 2] = 2 [2, 1] = 3 [1, 3] = 4 [2, 2] = 5 [3, 1] = 6 [2, 3] = 7 [3, 2] = 8 [3, 3] = 9 what is the name of this kind of shorting order? I agreed now that its not in lexicographical order.

This is definitely not lexicographic, which would be $11,12,13,21,22,23,31,32,33$.

What you are doing can be thought of as follows. Create a $n \times n$ matrix of indices, and enumerate it by diagonal _strips_ from upper left to lower right corners. I don't think there is a specific name for this traversal.