A.61 library(ugraphs): Graph manipulation library
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Availability::- use_module(library(ugraphs)).(can be autoloaded)
Source[det]neighbors(+Vertex, +Graph, -Neigbours)
[det]neighbours(+Vertex, +Graph, -Neigbours)
Neigbours is a sorted list of the neighbours of Vertex in Graph. Example: 
?- neighbours(4,[1-[3,5],2-[4],3-[],
                 4-[1,2,7,5],5-[],6-[],7-[],8-[]], NL).
NL = [1,2,7,5]
ClioPatria (version V3.1.1-51-ga0b30a5)