#rotate

Question 1: Single choice

hardAI-checkedKnowledge Representation & Reasoning

RotatE models each relation as an element-wise rotation in the complex plane: $\mathbf{e}_o \approx \mathbf{e}_s \circ \mathbf{r}$ with $|r_k| = 1$ , i.e. $r_k = e^{i\theta_k}$ . What must hold for a relation $r$ that is symmetric, so that $(s, r, o)$ and $(o, r, s)$ both fit?

$\mathbf{r} \circ \mathbf{r} = \mathbf{1}$ , so every $\theta_k$ is 0 or $\pi$ 1
Every $\theta_k$ equals $\pi/2$ , a quarter turn in each coordinate2
The relation vector is the zero vector, so it adds nothing3
The magnitudes $|r_k|$ exceed 1, so that the rotations also stretch the vectors4

Timed test