The identity matrix is the matrix for which a_ij = 1 when i = j, and 0 everywhere else. For example, in three dimensions, I = [[1 0 0 ; 0 1 0 ; 0 0 1]].
Here is a column vector: [[0 1 0]]'.
x \mapsto y_1...y_n
1/3
1 + 1 = 2
1 \leq 3 - 1
\leq 5
\begin{graph}
rankdir=LR
v_1
v_1 -> v_2
v_2 -> v_3
v_3 -> v_1
\end{graph}
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