how to identify t0 and t1?

[gscabanne]

Hi, I am working with IMa2. I have the following populational topology ((0,1):4,(2,3):5):6 and I am interested in the time divergence between 0 and 1, as well as  between  2 and 3. According to the IMa2's manual "The ancestral populations are numbered beginning with npops for the most recent ancestral population and proceeds up to..." What is puzzling here is that, according to this explanation, the population with the label "npops" (in the example 4) should be the "most" recent. Isn't it circular? In the example I dont know which divergence (between 0 and 1, or 2 and 3), is the most recent. So,. how do I name the first ancestral pop according to the criterion of "most" recent ancestral? Another aspect of this question...how do I know to what node give t0 and t1? 

Or, does it mean that t0 will be always associtated to the first ancestral population? a population that I named as npops?

I will appreciate your help.

Gustavo S Cabanne