( 790 ) 
arbitrary point and for values of a, consecutive to a", we determine 
y, in such a way, that the latter point lies inside it; if this is 
possible up to y©, we stop at '/, (@” + a) = a, and we continue 
this process in the same way until it leads after a denumerable 
number of steps to an end. 
This series of y.’s can in general be chosen in different ways; 
the value ap, where it ends, lies then either before a,, or it coin- 
cides with a,. 
We shall now investigate such a series of domains y, more closely 
and we shall suppose that from «,‚ as far as and inclusive of a, no 
invariant point is situated on the curve £, resp. A's. 
If we describe the boundary of a domain y, in opposite direction 
of the hands we find it consisting alternately of ares and points 
belonging to both 4, and to #', and which we shall call dividing 
arcs (which are of course closed sets of points) resp. dividing points, 
of arcs belonging only to &, (being not closed sets of points) which 
we shall call inner arcs of kz, and of curves belonging only to 4,, 
which we shall call inner arcs of k',. To the above mentioned circuit 
of y, corresponds an order of succession of the inner ares of 4,, 
belonging to a circuit of &, with the hands, and an order of succes- 
sion of the inner ares of £,, belonging to a circuit of 4", in opposite 
direction of the hands. 
The part of 4, resp. 4',, not belonging to the dividing ares, dividing 
Aaya = L 
Er Se Se Eine Be WET i BATT From: 
Z Gr à IN 
Ze = 
u \ 
/ ) 
) Ze ) 
| / 
\ en / 
\ - fe AE JN 
3 7 ine AON 
IN vs \ Sie \ 6, Tbe 4 
Ss No Zl \ 4 De 
\J } \ == JA 7 
EL Sn De NG 
eS 
