Homework 2 corrections

Look at the K-book chapter 2 page 14 exercise 2.3 ( Excision for $K_{0}$ and how to make a non-unital ring unital)

In the exact sequence $K_{0} (R, I) \overset{π_{2 *}}{\to} K_{0} (R) \to K_{0} (R / I)$

$π_{2} : D_{R} (I) \to R$ is given by $π_{2} (x, y) = y$ and $π_{2 *} [-] = [R \otimes_{D_{R} (I)}^{π_{2}} -]$

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