94
PYTHAGOREAN ARITHMETIC
((3) The ¿Trdvdrj/xa {‘bloom’) of Thymaridas.
Thymaridas of Paros, an ancient Pythagorean already
mentioned (p. 69), was the author of a rule for solving a
certain set of n simultaneous simple equations connecting n
unknown quantities. The rule was evidently well known, for
it was called by the special name of kndvOppa, the ‘ flower ’ or
‘bloom’ of Thymaridas. 1 (The term kirdvOppa is not, how
ever, confined to the particular proposition now in question;
Iamblichus speaks of errai/Oppara of the Introductio arith
metica, ‘arithmetical kirai/dijpaTa’ and kiTavOrjpara of par
ticular numbers.) The rule is stated in general terms and no
symbols are used, but the content is pure algebra. The known
or determined quantities {¿»pLcrpevor) are distinguished from
the undetermined or unknown {dopia-jov), the term for the
latter being the very word used by Diophantus in the expres
sion irXyOos povdScov dopuTTov, ‘ an undefined or undetermined
number of units’, by which he describes his dpiQpoy or un
known quantity (= x). The rule is very obscurely worded,
but it states in effect that, if we have the following n equa
tions connecting n unknown quantities x, x x , x 2 . . . x n _ x ,
namely
X + x x + x 2 +... + x n _ x = s,
x + x x = a x ,
x + x 2 = a 2
x T x n _ x — a n _ x ,
the solution is given by
(cq + a 2 + ... + j) — s
X ~ n— 2
Iamblichus, our informant on this subject, goes on to show
that other types of equations can be reduced to this, so that
the rule does not ‘ leave us in the lurch ’ in those cases either. 2
He gives as an instance the indeterminate problem represented
by the following three linear equations between four unknown
quantities:
x + y = a {z + u),
x + z = h (u + y),
x + u= c(y + z).
1 Iambi, in Nicorn., p. 62. 18 sq.
2 lb., p. 68. 16.