On Saturday, 18 June 2011 11:38:45 UTC+10, Owen Duffy wrote:
....
The ratio of V/I at the node where both lines are joined is given for a shunt stub by the inverse of the sum of the inverses of V/I for each.

That was a sidetrack, as Walt's example is a series stub and in that case, the V/I looking into the series combination is simply the sum of V/I for each.

Owen