ABSTRACT
The number of spanning sink-trees (source-trees) having the vertex Vj as sink (source) is equal to the value of the minor of the elements of the row of M'*' (column of M ~) corresponding to the vertex Vj. FVom the matrices above, V \ contains only sink-trees with vertex 1 as its sink, and source-trees with vertex 2 as its source. The number of spanning sinkand source-trees is 3 and 4, respectivdy. They are represented bdow.
