Final answer:
The edge where the inequality starts on a graph is represented by a boundary line or curve, such as the 45-degree dashed line on a Lorenz curve that represents perfect income equality. In general inequalities, this boundary can be inclusive (solid line) or exclusive (dashed line).
Step-by-step explanation:
The edge or barrier of a graph indicating where an inequality starts is typically represented by a boundary line or curve. In the context of Lorenz curves, which are used to illustrate income inequality, this boundary line represents what perfect equality of the income distribution would look like. This is shown as a 45-degree dashed line on a Lorenz curve. When discussing inequality in a mathematical sense, such as with inequalities on a number line or in a coordinate system, the line or curve that separates the two regions (where the inequality holds true and where it does not) is often referred to as the boundary. This can either be a solid line, indicating that the values on the line are included in the solution set (inclusive boundary), or a dashed line, indicating that the values on the line are not included in the solution set (exclusive boundary).