Factorial !

Returns the factorial of its argument:

$$\begin{eqnarray*} 0! & = & 1\\ n! & = & \prod_{i=1}^{n}i\\ \end{eqnarray*}% WIDTH=87 HEIGHT=84$$

The operator can be placed on the canvas in two ways:

• From the Functions (``function'') toolbar; or
• By typing the letters ``fact'' on the canvas and then pressing the Enter key.

Note: $$n!=\Gamma(n+1) \end{displaymath}% WIDTH=325 HEIGHT=29$$ which is how it is implemented in Minsky.

Minsky provides this function because of its relationship to the derivative of the Gamma function (and factorials).