public static boolean isTipNode( LeftTupleNode node, TerminalNode removingTN ) {
        return NodeTypeEnums.isEndNode(node) || isNonTerminalTipNode( node, removingTN );
    }
public static boolean isTipNode ( LeftTupleNode node , TerminalNode removingTN ) { return NodeTypeEnums . isEndNode ( node ) || isNonTerminalTipNode ( node , removingTN ) ; }
Returns whether the node is the tip of a segment.
EndNodes (rtn and rian) are always the tip of a segment.

node cannot be null.

The result should discount any removingRule. That means it gives you the result as
if the rule had already been removed from the network.