The invariant subspace problem is a little more complicated: it is about spaces with an infinite number of dimensions, and it asks whether every linear operator (the equivalent of a matrix ...

So that’s an invariant subspace. The invariant subspace problem is a little more complicated: it is about spaces with an infinite number of dimensions, and it asks whether every linear operator (the ...

To reach their mainframes you'll be using crude robots, Command Prompt programming, and multilinear subspace coprocessors. I've no clue what that last one is but a quick google brings up this.