A miniature recurrent layer holds a two-number state and updates it by the same matrix at every step:
| Symbol | Meaning |
|---|---|
| activation of unit 1 after steps | |
| activation of unit 2 after steps |
After five steps the state is , so the whole five-step behaviour is packed into the single matrix . You want the cross term: the entry in row 1, column 2 of , which says how strongly unit 2's starting activation feeds into unit 1 five steps later.
is diagonalizable and both of its eigenvalues are integers, so for some invertible and diagonal .
What is the entry of in row 1, column 2? Your answer is an exact integer.