A constraining facet is an optional property than be applied to constrain a value space.
Sometimes this constrain will constrain the lexical space
For example, to restrict to the even integers between 1 and 100:
Use the minInclusive/maxInclusive to restrict the range to 2-100
Use a regular expression to restrict the last digit to 0, 2, 4, 6, or 8.
The next few slides will go through the constraining facets.