526 
number may be also zero, we imagine e.g. the bundles P, Q, R 
and S to be omitted from fig, 3. 
B. Curve (M) is a limit-curve of the (J/)-bundle | fig. 4). 
We find in fig. 4 besides the (J/)-bundle, still the bundles P, Q 
and F; of each of those bundles, however, one curve only is drawn. 
Now we see easily that at the one side of the (J/)-bundle always 
one bundle more than at the other side must be situated. 
‘ 
When we summarise the previous considerations, then we find 
the following three principal types. 
I. Curve (M/) is monodirectionable (tig. 1) 
(M) 
Fig. 3. Fig. 4. 
The P,7-diagram of a system of 7 components has the same 
appearance as that of a system with 2—1 components. 
Il. Curve (M) is bidirectionable (figs. 2, 3, and 4). 
A. Curve (M) is a middlecurve of the (M) bundle (fig. 3). 
At both sides of the (J/)-bundle always a same number of bundles 
is situated, 
Consequently the P, 7-diagram consists of a (M)-bundle + n 
bundles of curves at the one and 2 bundles of curves at the other 
side. The (M)-bundle contains four curves at least. 
B. Curve (M) is a limit-curve of the (J/)-bundle (fig: 4). 
At the one side of the (M)-bundle [viz. at that side where is 
situated the (J/7)-curve| one bundle more than at the other side is 
always situated. 
The P,7-diagram consists, therefore, of a (J/)-bundle + 7 bundles 
