A transcendental number is a real or complex number that is not alg...
Ivan Niven was a Canadian-American mathematician, specializing in n...
It's interesting that we know $e$ and $\pi$ are transcendental numb...
It's actually not obvious that the product (or sum) of 2 algebraic ...
Is $i$ an algebraic number?
We showed above that the sum of 2 algebraic numbers is also an alge...
Note that if we expand expression (2) we get $$ 1+ ...+e^{\alp...
$$ \frac{d(e^{-x}F(x))}{dx}=-e^{-x}F(x)+e^{-x}F'(x)=\\ =-e^{-x}F(...
If we make the substitution $\xi = \tau x $ the integration limits ...
How does he end up with $kF(0)$?
This is not difficult to see because of the $x^{p-1}$ factor and al...
Note that $f(x)$ can be written as $$ f(x)=\frac{c^sx^{p-1}(cx...
Using expression (11) $$ F(\beta_j)=f(\beta_j)+f^{(1)}(\beta_j)...
As shown in a comment above, $f(x)$ can be written as $$ f(x)=...
Isn't a $\tau$ missing? I mean, shouldn't the integral be $$\int_...
We have finally reached a contradiction since the left side of (12)...
1939]
THE TRANSCENDENCE
OF
ir
469
for
XI-
X_X2,
with (x, y)
in a
neighborhood
of
CO,
and
y-yo(x)
and
y'-yoi(x)
not both
zero,
then
CO
furnishes
a proper
(or improper)
strong relative
minimum
for Jf=
f2f(x,
y, y')dx,
G(x, y,
y,
y,
y')-f(x,
y
y, y')-
)-(y-y)fV,(x,
y, y')
-
(y'
-')fy,
(x, y,
y'). Examples
were given
which
satisfy
these
sufficient
condi-
tions but
which do
not
yield
to classical
methods.
3. The finite
abstract
groups
in
which
every
subgroup
is invariant
(Hamil-
tonian
groups) are
well
known, as are also
the groups in which every
subgroup
is abelian. Classifying
the finite abstract
groups
according
to the number
of
complete
sets
of
non-invariant
conjugate
subgroups
contained
in them,
Pro-
fessor Sigley discussed
the class of groups
which
contain a
single complete
set of
non-invariant
conjugate
subgroups.
Necessary
and
sufficient
conditions
that a
group
belong to
this class
were obtained.
4. It
was shown
by
Professor Finkel how the
derivatives
of ax
and
sin-' x
may
be derived
directly by
the A-process,
without
reverting
to the derivatives
of
the
logarithmic
and sine functions.
5.
Mr. Gillam
sketched
a development
of three-dimensional
analytic
euclid-
ean
geometry
(free
of
coordinates)
with
"point"
as the single
undefined
element
and "distance"
as the
only primitive
relation.
Lines
and planes
were defined
as
determinantal
loci.
6. Mr. Wulftange
presented
a new
method
for the numerical
solution of
quadratic
congruences
which
is
believed
to possess
certain practical
advantages.
L.
M.
BLUMENTHAL,
Secretary
THE
TRANSCENDENCE
OF
c
IVAN
NIVEN,*
University
of Pennsylvania
Among the
proofs of
the transcendence
of e, which
are in
general variations
and simplifications
of the original
proof
of
Hermite,
perhaps
the
simplest
is
that
of A.
Hurwitz.t
His solution
of the problem
contains
an ingenious
device
which
we
now employ
to obtain
a
relatively
simple proof
of the transcendence
of 7r.
We assume
that
ir
is
an
algebraic
number,
and
show
that
this leads to
a
con-
tradiction. Since
the
product
of two
algebraic
numbers
is an
algebraic
number,
the
quantity
i7r
is a
root
of an algebraic
equation
with
integral
coefficients
(1)
01(x)
=
O,
whose
roots
are
aci=ir,
a2, a3,
* *
a.n
Using Euler's
relation e$r+1
=0,
we
have
(2)
(eal
+
1)(ea2
+
1) *
(ean
+
1)
=
0.
We now
construct an
algebraic
equation
with integral
coefficients whose
roots
are
the
exponents
in the
expansion
of
(2).
First consider
the
exponents
(3)
ai
+
a2,
ai
+
as,
a2
+
C
.
.
*
an-1
+ an
*
Harrison
Research Fellow.
t
A.
Hurwitz,
Beweis der Transendenz
der
Zahl
e,
Mathematische
Annalen,
vol.
43,
1893,
pp. 220-221
(also in his Mathematische
Werke,
vol. 2, pp.
134-135).
470 THE
TRANSCENDENCE
OF 7w
[October,
By equation (1), the elementary symmetric functions of
a,,
a2,
,
*? are
ra-
tional numbers. Hence the elementary symmetric functions
of the
quantities
(3)
are rational numbers. It follows that the quantities (3)
are
roots
of
(4)
02(x)
=
0,
an
algebraic equation with integral coefficients. Similarly, the sums of
the
a's
taken three at a time are the nC3 roots of
(5)
03(X)
=
0
Proceeding thus, we obtain
(6) 04(X)
=
0,
05(X)
=
0,
,
.
.
v 0,(X)
=
0,
algebraic equations with integral coefficients, whose roots are the sums of the a's
taken 4, 5,
,
n at a time respectively. The product equation
(7) 61(X)02(X)
.
..(x)
=
0
has roots which are precisely the exponents in the expansion of (2).
The deletion of zero roots (if any) from equation (7) gives
(8)
0(X)
=
cxr
+
ClXr-l
+ + Cr 0,
whose
roots /i,
02
O
* r
are the
non-vanishing exponents
in
the
expansion
of
(2), and whose coefficients
are
integers.
Hence
(2) may be written
in the form
(9)
e#1
+
e#2
+
...
+
er
+
k=
0
where k is a positive integer.
We
define
( 10) ~~~~~~~~csxP1I{6(
x)
}
P~
(10)
f(x)
-
(sp- i)!
1
where s
=
rp -1, and p
is
a prime to be specified. Also we define
(11)
F(x)
=
f(x)
+
f(')(x)
+
f(2)(x)
+
.
. .
+
f(s+p+l)(x)
noting, with thanks to Hurwitz, that the derivative of e-xF(x) is
e-xf(x).
Hence we may write
e-xF(x)
-
eF
(0)
=
f
-
e-f(t)d
.
The
substitution t
=
-x produces
F(x)
-
exF(O)=
- X
e(1-7)x
f(rx)dT
.
Let x
range over
the
values
31,/2,
.2
,
* r
and add
the
resulting equations.
Using
(9).
we
obtain
1939]
THE TRANSCENDENCE OF
1r
471
rr
r
1
(12)
1
F
+
kF(O)
=
-E:
j
e
(l-T)#if(
rfj)dr.
j=l
j=j
This
result gives
us the
contradiction
we
desire.
For we shall
choose the prime
p
to make
the left
side a
non-zero
integer,
and the
right side
as small
as we
please.
By (10), we
have
Zf(t)@D
=0,
for
0
<
t
<
p.
j=l
Also
by (10)
the polynomial
obtained
by multiplying
f(x)
by
(p
-
1)!
has
in-
tegral
coefficients.
Since
the product
of
p consecutive
positive
integers
is
divisi-
ble by p!, the
pth and
higher
derivatives
of (p -l1)!f(x) are
polynomials
in x
with integral
coefficients
divisible
by p!.
Hence
the pth
and higher
derivatives
of
f(x)
are polynomials
with integral
coefficients
each of
which is
divisible by
p.
That
each of
these coefficients
is also divisible
by c8 is obvious
from
the
defini-
tion
(10). Thus
we have
shown
that,
for t_p,
the quantity
f(t)(Bij)
is a
poly-
nomial
in
/3s of
degree
at most
s, each
of whose
coefficients
is divisible
by
pco.
By (8),
a symmetric
function
of
,i,
132,
Oir
with integral
coefficients
and of
degree
at most
s is an
integer
provided
each
coefficient is divisible by c8
(by
the
fundamental
theorem
on
symmetric
functions).
Hence
f(t)()
= pk,
(t= p,p
+ 1, ,
p +
s),
j=l
where the
kt
are integers.
It follows
that
r
p+s
F
F(o
j)
=
p
E
kt .
In
ordrtcmpltehet=p
In
order to
complete
the
proof
that the left
side of (12)
is
a non-zero
integer,
we now show that
kF(O)
is an integer
prime
to
p. From
(10)
it is clear that
f(t)(0)
=
0,
(t
=
O,
1, ,
p
-
2),
f(P-1)(0)
=
COCrp,
f(t)(0)
=
pKt,
(t
=
p,
p
+
1,
,
p
+
s),
where
the
Kt
are integers.
If p
is chosen
greater
than
each of k,
C, Cr (possible
since the number
of primes
is infinite),
the desired
result
follows
from (11).
Finally, the
right side
of (12)
equals
f f
{
J
Cr3
(7-1) e(lT):jdr.
j=1
c
o
(p-1)!
This
is
a finite
sum, each
term
of which
may
be made
as
small as we
wish
by
choosing
p very
large,
because
{Cr 0io(-rj)}
lrm
3
=
0.
P-409
(p -
1)!

Discussion

If we make the substitution $\xi = \tau x $ the integration limits $\xi = 0 \rightarrow \tau =0$ and $\xi = x \rightarrow \tau =1$. If we multiply both sides of the equation by $e^{x}$ we get this expression. How does he end up with $kF(0)$? If you start with (9) $$ e^{\beta_1}+...+e^{\beta_r}+k=0 \equiv\\ k=-(e^{\beta_1}+...+e^{\beta_r})\equiv \\ kF(0)= -\sum e^{\beta_i}F(0) $$ How do you prove the limit is zero? $$ \frac{d(e^{-x}F(x))}{dx}=-e^{-x}F(x)+e^{-x}F'(x)=\\ =-e^{-x}F(x)+e^{-x}(F(x)-f(x))=-e^{-x}f(x) $$ In fact it is known that one of those two numbers $e\pi$ or $\pi +e$ is transcendental. Note that if we expand expression (2) we get $$ 1+ ...+e^{\alpha_i+\alpha_j}+e^{\alpha_i+\alpha_j+\alpha_k}+...e^{\overbrace{\alpha_i+...+\alpha_l }^{n}}=0 $$ We showed above that the sum of 2 algebraic numbers is also an algebraic number and so it is possible to create a polynomial $\theta_2(x)$ whose roots are $\alpha_i+\alpha_j$. The same applies to the sum of 3,4,...n algebraic numbers. This is not difficult to see because of the $x^{p-1}$ factor and also because $\theta(\beta_j) = 0$. Yes Mike, for instance if you have the polynomial $f(x)=x^2+1$, the coefficients are rational and the roots are $i$ and $-i$. That's true, but the argument here is just based on the fact that coefficients of a polynomial are (up to a sign) the elementary symmetric functions on its roots. Isn't a $\tau$ missing? I mean, shouldn't the integral be $$\int_0^1\frac{\{c^r\beta_j\tau\theta(\tau\beta_j)\}^p}{\beta_j\tau(p-1)!}e^{(1-\tau)\beta_j}d\tau$$? Luis. Any reference to the latter fact? It's interesting that we know $e$ and $\pi$ are transcendental numbers but no one has proved that $\pi+e$ or $e\pi$ are transcendental. A transcendental number is a real or complex number that is not algebraic - that is, it is not a root of a non-zero polynomial equation with rational coefficients. Check out this video touching on that topic: [![](https://i.ytimg.com/vi/ZxA-xD9mUmM/maxresdefault.jpg)](https://www.youtube.com/watch?v=ZxA-xD9mUmM) It is not obvious to me why the resultant is a polynomial in t with rational coefficients. Using expression (11) $$ F(\beta_j)=f(\beta_j)+f^{(1)}(\beta_j)+...+f^{(s+p+1)}(\beta_j) $$ and knowing that $\sum^{r}_{j=1}f^{(t)}(\beta_j)=0$ for $0\leq t<p$ we get $$ \sum^{r}_{j=1} F(\beta_j)=\sum^{r}_{j=1} f(\beta_j)+ \sum^{r}_{j=1} f^{(1)}(\beta_j)+...+ \sum^{r}_{j=1} f^{(s+p+1)}(\beta_j) $$ All the sums where the derivatives have an order $<p$ will be zero. If now we use the result $\sum^{r}_{j=1}f^{(t)}(\beta_j)=pk_t$, we end up with $$ \sum^{r}_{j=1} F(\beta_j)=p\sum^{p+s}_{t=p}k_t $$ We have finally reached a contradiction since the left side of (12) is an integer and the right side is as small as we wish by choosing a very large $p$, which means that $\pi$ cannot be an algebraic number! One way of understanding this limit is thinking about the exponential as $\sum_{n=0}^{\infty}\frac{x^n}{n!}=e^x$. This is a convergent series which means that the weight of the terms with large $n$ will have to tend to zero, otherwise it would diverge. $$ \lim_{n \rightarrow \infty} \frac{x^n}{n!} = 0 $$ This is exactly the same limit we have in the paper if we do $x=c^r\beta_j\theta(\tau\beta_j)$. Is $i$ an algebraic number? Note that $f(x)$ can be written as $$ f(x)=\frac{c^sx^{p-1}(cx^r+...+c_r)^p}{(p-1)!} $$ The highest term in $f(x)$ is of the form $x^{p-1}x^{rp}=x^{p+s}$. $$ f(x)=\frac{c^s(wx^{p+s}+...+w_rx^{p-1})}{(p-1)!} $$ where $w,...,w_r$ are integers that have resulted from expanding the expression $(cx^r+...+c_r)^p$. It's not difficult to see that for any derivative higher than $p$ the coefficients will be divisible by $pc^s$. As shown in a comment above, $f(x)$ can be written as $$ f(x)=\frac{c^s(wx^{p+s}+...+w_rx^{p-1})}{(p-1)!} $$ Since the lowest term in $f(x)$ is of order $p-1$, $f^{(t)}(x)$ for $t<p-1$ will always have terms in $x$ and so $f^{(t)}(0)$ will of course be zero. $f^{(p-1)}(0)=\frac{(p-1)!c^s w_r}{(p-1)!}$ where $w_r$ is the last term in the binomial expansion of $(cx^r+...+c_r)^p$ and so $w_r=c_r^p$. Finally for $t\geq p$, $f^{(t)}(0)$ will only have one term that will not vanish, the term of order $t$. The result is simply a product of $p$, $c^s$ and the binomial expansion term $w_t$. All the terms are integers and so we can group in the form $pK_t$, where $K_t$ in an integer. It's actually not obvious that the product (or sum) of 2 algebraic numbers is also an algebraic number. To prove this let's first define the Resultant $R(f,g)$ of 2 polynomials $f(x)=a_0x^n+...+a_n$ and $g(x)=b_0x^m+...+b_m$ with $a_0b_0 \neq 0$ as $$ R(f,g) = a_0^mb_0^n \prod_{ij}(\alpha_i-\beta_j) $$ where the $\alpha_i$ are the roots of $f(x)$ and $\beta_j$ are the roots of $g(x)$. It's not difficult to notice that if the 2 polynomials f and g have a root in common the resultant will be zero. To prove that the sum of 2 algebraic numbers is also an algebraic number we need to find a polynomial whose roots are $\alpha_i+\beta_j$. To construct such polynomial we will use the resultant of $f(x)$ and $g(t-x)$ $$R(f(x),g(t-x))$$ Now if we do the transformation of variables $x \rightarrow t-x$ the roots of $g(t-x)$ will be $t-\beta_j$ and so $$R(f(x),g(t-x))= a_0^mc_0^n \prod_{ij}(\alpha_i-(t-\beta_j))=\\ =a_0^mc_0^n \prod_{ij}(\alpha_i+\beta_j-t) $$ Now, it's not difficult to see that the resultant itself will be a polynomial in $t$ of degree $mn$ with roots $\alpha_i+\beta_j$. To prove that the product of 2 algebraic numbers is also an algebraic number we use a different resultant: $$ R(f(x),x^mg(t/x)) $$ $$ x^mg(1/x)=b_0+...+b_mx^m $$ The roots of $x^mg(1/x)$ are $1/\beta_j$ and so the roots of $x^mg(t/x)$ are $t/\beta_j$. If we now plug that into the resultant we get a polynomial with degree $mn$ in t whose roots obey the equation: $$ \alpha_i-t/\beta_j=0\\ t=\alpha_i\beta_j $$ Ivan Niven was a Canadian-American mathematician, specializing in number theory. He is famous for completing the solution of most of Waring's problem in 1944. He also has an Erdős number of 1 because he has coauthored a paper with Paul Erdös. ![](https://upload.wikimedia.org/wikipedia/commons/6/6e/Ivan_Niven.jpg)