This site contains: mathematics courses and book; covers: image analysis, data analysis, and discrete modelling; provides: image analysis software. Created and run by Peter Saveliev.

From Intelligent Perception

Given two sets $X$ and $Y$. Then $X×Y$ is the set of all pairs $(a,b)$ of elements in $X$ and $Y$ respectively. The functions $p_X: X×Y → X$ and $p_Y: X×Y → Y$ given by $p_X(a,b) = a, p_Y(a,b) = b$ are called the projections.

See also:

• New sets from old
• Projection maps.