lojix/logic/src/main/com/thesett/aima/logic/fol/Functor.java
public boolean isGround()
    {
        for (int i = 0; i < arity; i++)
        {
            if (!arguments[i].isGround())
            {
                return false;
            }
        }

        return true;
    }
public boolean isGround()
    {
        for (int i = 0; i < arity; i++)
        {
            if (!arguments[i].isGround())
            {
                return false;
            }
        }

        return true;
    }
Reports whether or not this term is a ground term. Constants (functors of arity zero) and numbers are ground
terms, as are functors all of the arguments of which are ground term.

@return <tt>true</tt> if this functor is a ground term, <tt>false</tt> othewise.