Hint 4 TUCKER3

Suggestions on how to discuss the problem
Use the operations for factor rotation discussed in How-To #3 

Use matrix operations to check the premisses
If you have orthogonal factors, you may use the squares of the core elements, otherwise you have to compute the models by constructed cores, and subtract the model from the real data to estimate the error.

Use either a specially designed core, or clever application of Eq. (4).