Indifference curve

Summary

An indifference curve for a bundle $\left( x_1,x_2 \right)$ is the collection of all bundles $\left( y_1,y_2 \right)$ for which $\left( y_1,y_2 \right)∼\left( x_1,x_2 \right)$ ,

$$\{ \left( y_1,y_2 \right)∈R^2 | \left( y_1,y_2 \right)∼\left( x_1,x_2 \right) \}$$