In article , Arthur Figgis
] writes
but would the two lines have to be joined to constitute a network? The
mathematical types I know weren't sure.

From my rather rusty memory, it depends entirely on context. Some
theorems on networks require them to be connected (i.e. ignoring
directional arrows, there must be a path between any two points in the
network) while others don't.

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Clive D.W. Feather | Home:
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