Changes

For example, overlaying the corresponding dual graphs on the plane-embedded graphs shown above, we get the following composite picture:

For example, overlaying the corresponding dual graphs on the plane-embedded graphs shown above, we get the following composite picture:

{| align="center" cellpadding="10"

| [[Image:Logical_Graph_Figure_4_Visible_Frame.jpg|500px]]

|}

` ` ` ` ` | ` ` ` ` ` | ` ` ` ` ` ` ` ` ` ` ` ` ` `

` ` ` ` ` | | ` o ` | | ` ` ` = ` ` ` ` ` ` ` ` ` `

` ` ` ` ` | | ` | ` | | ` ` ` ` ` ` ` ` ` ` ` ` ` `

` ` ` ` ` | o---|---o | ` ` ` ` ` ` ` ` ` ` ` ` ` `

For a number of pragmatic reasons it is convenient to single out the outermost region of the plane in a distinctive way and to mark it as the ''root node'' of the corresponding dual graph, indicated in the above Figure by the ''amphora'' or ''at'' sign, "@".

For a number of pragmatic reasons it is convenient to single out the outermost region of the plane in a distinctive way and to mark it as the ''root node'' of the corresponding dual graph, indicated in the present text by means of a horizontal strike-through.

Extracting the dual graph from its composite matrix, we get this picture:

Extracting the dual graph from its composite matrix, we get this picture: