1938, Ralph Boas.

Problem: To Catch a Lion in the Sahara Desert.

We place a locked cage onto a given point in the desert. After that we introduce the following logical system:

Axiom 1: The set of lions in the Sahara is not empty.

Axiom 2: If there exists a lion in the Sahara, then there exists a lion in the cage.

Procedure: If P is a theorem, and if the following is holds: "P implies Q", then Q is a theorem.

Theorem 1: There exists a lion in the cage.

We place a spherical cage in the desert, enter it and lock it from inside. We then perform an inversion with respect to the cage. Then the lion is inside the cage, and we are outside.

Without loss of generality we can view the desert as a plane surface. We project the surface onto a line and afterwards the line onto an interior point of the cage. Thereby the lion is mapped onto that same point.

Divide the desert by a line running from north to south. The lion is then either in the eastern or in the western part. Lets assume it is in the eastern part. Divide this part by a line running from east to west. The lion is either in the northern or in the southern part. Lets assume it is in the northern part. We can continue this process arbitrarily and thereby constructing with each step an increasingly narrow fence around the selected area. The diameter of the chosen partitions converges to zero so that the lion is caged into a fence of arbitrarily small diameter.

We observe that the desert is a separable space. It therefore contains an enumerable dense set of points which constitutes a sequence with the lion as its limit. We silently approach the lion in this sequence, carrying the proper equipment with us.

In the usual way construct a curve containing every point in the desert. It has been proven [1] that such a curve can be traversed in arbitrarily short time. Now we traverse the curve, carrying a spear, in a time less than what it takes the lion to move a distance equal to its own length.

We observe that the lion possesses the topological gender of a torus. We embed the desert in a four dimensional space. Then it is possible to apply a deformation [2] of such a kind that the lion when returning to the three dimensional space is all tied up in itself. It is then completely helpless.

We examine a lion-valued function f(z). Be \zeta the cage. Consider the integral
```
1 [ f(z)
------- I --------- dz
2 \pi i ] z - \zeta
C
```

```
```

```
...where C represents the boundary of the desert. Its value is f(zeta), i.e. there
is a lion in the cage [3].
```

`1.9 The Wiener-Tauber method`

```
```We obtain a tame lion, L_0, from the class L(-\infinity,\infinity), whose
fourier transform vanishes nowhere. We put this lion somewhere in the desert.
L_0 then converges toward our cage. According to the general Wiener-Tauner
theorem [4] every other lion L will converge toward the same cage.
(Alternatively we can approximate L arbitrarily close by translating L_0
through the desert [5].)

### 2 Theoretical Physics Methods

#### 2.1 The Dirac method

We assert that wild lions can ipso facto not be observed in the Sahara desert.
Therefore, if there are any lions at all in the desert, they are tame. We leave
catching a tame lion as an execise to the reader.

#### 2.2 The Schroedinger method

At every instant there is a non-zero probability of the lion being in the cage.
Sit and wait.

#### 2.3 The nuclear physics method

Insert a tame lion into the cage and apply a Majorana exchange operator [6] on
it and a wild lion.

As a variant let us assume that we would like to catch (for argument's sake) a
male lion. We insert a tame female lion into the cage and apply the Heisenberg
exchange operator [7], exchanging spins.

#### 2.4 A relativistic method

All over the desert we distribute lion bait containing large amounts of the
companion star of Sirius. After enough of the bait has been eaten we send a
beam of light through the desert. This will curl around the lion so it gets all
confused and can be approached without danger.

### 3 Experimental Physics Methods

#### 3.1 The thermodynamics method

We construct a semi-permeable membrane which lets everything but lions pass
through. This we drag across the desert.

#### 3.2 The atomic fission method

We irradiate the desert with slow neutrons. The lion becomes radioactive and
starts to diintegrate. Once the disintegration process is progressed far enough
the lion will be unable to resist.

#### 3.3 The magneto-optical method

We plant a large, lense shaped field with cat mint (nepeta cataria) such that
its axis is parallel to the direction of the horizontal component of the
earth's magnetic field. We put the cage in one of the field's foci. Throughout
the desert we distribute large amounts of magnetized spinach (spinacia
oleracea) which has, as everybody knows, a high iron content. The spinach is
eaten by vegetarian desert inhabitants which in turn are eaten by the lions.
Afterwards the lions are oriented parallel to the earth's magnetic field and
the resulting lion beam is focussed on the cage by the cat mint lense.

### A supplementary contribution to the mathematical theory of Big Game Hunting

#### I. Software Engineering Methods

1. The iterative method. Construct a suitable cage around a portion of the
desert. Determine whether there is a lion in the cage. If there is no lion
in the cage, rebuild the cage around an adjacent portion of the desert. Repeat
as necessary until there is a lion in the cage.

2. The recursive, or project management method. Construct a cage and
establish a deadline by which time a lion will be captured. If no lion is
captured before the deadline, let the deadline slip by one month. Repeat as
necessary.

#### II. Methods from Political and Social Science

3. The Pentagon method. Construct a safe, secure cage and leave the door
open. Alternate massive B-52 strikes across the Sahara desert with subtle
propaganda campaigns emphasizing the safety and security of your cage.
When a lion enters the cage, close and lock the door.

4. The supply-side method. Distribute vast quantities of lion food and
eliminate all threats to the lion population. Put a cage in the desert
and wait for the explosive growth of the lion population to force a lion
into the cage.

5. The Marxist-Leninist method. Indoctrinate the gazelle population of
the Sahara desert in dialectical materialism. Disguise your cage as a
re-education camp for capitalist lions, and the gazelles will bring you
all the lions you need.

[1] After Hilbert, cf. E. W. Hobson, "The Theory of Functions of a Real Variable and the Theory of Fourier's Series" (1927), vol. 1, pp 456-457

[2] H. Seifert and W. Threlfall, "Lehrbuch der Topologie" (1934), pp 2-3

[3] According to the Picard theorem (W. F. Osgood, Lehrbuch der Funktionentheorie, vol 1 (1928), p 178) it is possible to catch every lion except for at most one.

[4] N. Wiener, "The Fourier Integral and Certain of itsl Applications" (1933), pp 73-74

[5] N. Wiener, ibid, p 89

[6] cf e.g. H. A. Bethe and R. F. Bacher, "Reviews of Modern Physics", 8 (1936), pp 82-229, esp. pp 106-107

[7] ibid