This demonstration, by Jocelyn Ireson-Paine, generates a categorical product of two sets and shows its universality. To run it, press the button in the form below. If you want, you can type sets into the input fields first, as explained below. Pressing the button will send a request to my Web server, which will send back a copy of this page with a link in green at the top pointing to your results. Clicking on this link will display these in a new browser window, or (depending on your browser) a new browser tab. If the demonstration's input checking detects an error such as a badly-formed set, it will report it in red.
The demonstration does not use Java or JavaScript, so should work in any browser. If it doesn't, then either I'm updating them, or the server machine is overloaded, so do please try again.
To enter a set into an input field, type either random (the
field's default value, which generates a set or function at random),
or randomne (which generates a non-empty
set at random),
or elements separated by space or comma. Leave the
field empty for the empty set. Elements must start with a letter,
which can optionally be followed by one or more letters or digits.
Extra spaces are allowed anywhere; and you may, but don't
have to, enclose sets in square or curly brackets.
Here are some
examples:
random: generates a set at random.
randomne: generates a non-empty set at random.
a,b,c or a b c or a, b , c or
{ a,b c}:
the set {a,b,c}.
{}: the empty set.