#Please insert up references in the next lines (line starts with keyword UP) UP arb.hlp UP glossary.hlp #Please insert subtopic references (line starts with keyword SUB) # Hypertext links in helptext can be added like this: LINK{ref.hlp|http://add|bla@domain} #************* Title of helpfile !! and start of real helpfile ******** TITLE Trees OCCURRENCE ARB_NT DESCRIPTION A tree consists of two types of 'nodes': - tips or terminal nodes: species connected to exactly one father - inner nodes: hypothetical ancestors connected to one father (and in the binary case to two children). A group_name may be assigned to an inner node; in this case, the node and all its children become a group. There are significant differences between phylogenetic trees and binary trees: phylogenetic trees binary trees: ------------------------------------------------------------------------- unrooted rooted inner nodes have n children all inner nodes have two children Since binary trees are much easier to handle, ARB converts phylogenetic trees to binary trees.