36 ADDITION TO MR ROWES MEMOIR ON ABEl/s THEOREM. [713
We have here — > —; each 0 f these being: less than 1, we have 1—— <1—— ,
/¿5 /¿6 /^5 № 6
that is, or —>—and so
fi 5 /¿6 fi 5 iu 5 fig — m 6
/¿7 /As ^ /Ai
¡1 7 — m 7 Ia 6 ~ w 6 yu-5 — m 5 '
Hence considering the two sets
/ \ / M-fi \ w e (fx 6 - r«jj)
(2 — y^~ m aJ and ( 0 — y^ e ~ me J >
a partial branch of the first set gives with a partial
intersections: and the number thus obtained is
branch of the second set
fh
/A; Vie,
n 5 (jjl 5 - m 5 ). n 6 (/x 6 - m 6 ). —, = n 5 n 6 fx 6 (fi B - m B ).
/¿6 m 6
For all the sets the number is
n 5 n 6 fx 6 Os - m s ) + n 5 n 7 /x 7 - m B ) + n B n 7 fi 7 (fx 6 - m 6 )
or taking this twice, the number is
= 2 %"n r fi r n 8 fi s — 2%"n r m r n s ix s
s>r
where in the first sum the 2" refers to each pair of suffixes. Adding the foregoing
value
2 "n 2 fi 2 — 2' 'rfm/jL — 2'V,
the whole number for the singularity in question is
= (2 /, Wya) 2 — 2"iifi — S"ri 2r mfjL — Tt"n r m r n s yug;
s>r
and the proof is thus completed.
Referring to the foot-note (ante, p. 31), I remark that the theorem y = deficiency,
is absolute, and applies to a curve with any singularities whatever: in a curve which
has singularities not taken account of in Abel’s theory, the “quelques cas particulars
que je me dispense de considerer,” the singularities not taken account of give rise
to a diminution in the deficiency of the curve, and also to an equal diminution of
the value of y as determined by Abel’s formula; and the actual deficiency will be
= Abel’s y — such diminution, that is, it will be = true value of y.