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.

# Subset

A set $A$ is a subset of set $X$ if every element of $A$ is also an element of $X$.
For every subset $A$, such function is defined as inclusion.
Given a function $f:X \rightarrow Y$, for every subset $A$ such function as restriction is defined.