Naqshbandi Golden Chain Naqshbandi Golden Chain The Naqshbandi Golden Chain is a lineage of spiritual masters of the Naqshbandi Sufi order related to each other going back to the Islamic prophet Muhammad It is a chain in which each scholar was given "ijazah" or permission for dhikr of God by his own teacher or pir to transmit the knowledge he had received to the next generation of students in the traditional manner of Sufi transmission. The Golden Chain, as different from all other Sufi lineages, is unique in that it stems from the first Caliph, Abu Bakr. From Abu Bakr, the secret of
Spanning tree and "routing loops", many routing protocols designed for such networks—including the Spanning Tree Protocol, Open Shortest Path First, Link-state routing protocol, Augmented tree-based routing, etc.—require each router to remember a spanning tree. A special kind of spanning tree, the Xuong tree, is used in topological graph theory to find graph embeddings with maximum genus. A Xuong tree is a spanning tree such that, in the remaining graph, the number of connected components with an odd number of edges is as small as possible. A Xuong tree and an associated maximum-genus embedding can be found in polynomial time. A tree is