Compute for |

(2) For |

(3) Replace the node in that contains nodes with the Path . |

If , then remove and introduce new nodes with links |

for . |

(4) Connect path to . For any tree or cycle link in , let |

be the set of nodes in , or if is an empty node, the nodes in any nonempty |

node reachable from by some path of links disjoint from a cycle containing |

. Find the subset such that and connect to . |

(5) Label the nodes of . Let be the set of nodes mapped to in . |

Update by for all . All other mappings remain |

unchanged. |

(6) Remove all empty nodes of degree and all empty 2-way cut nodes by contracting |

an adjacent tree link (a node is an -way cut node if its removal separates the graph into |

connected parts). Replace all empty 3-way cut nodes with 3 cycles. |