public abstract void setLeftChild(MyTreeSet <T> left);
public override void setRightChild(MyTreeSet <T> right) { this.rightChild = (MyTreeSetImpl <T>)right; }
public abstract void setRightChild(MyTreeSet <T> right);
public override void setLeftChild(MyTreeSet <T> left) { this.leftChild = (MyTreeSetImpl <T>)left; }