http://bjornsmaths.blogspot.com/2005/11/how-to-catch-lion-in-sahara-desert.html wrote:
How to catch a lion in the Sahara desert:
1) The method of inverse geometry: We place a spherical cage in the desert and enter it. We then perform an inverse operation with respect to the cage. The lion is then inside the cage and we are outside.
2) The set theoretic method: We observe that the desert is a separable space. It therefore contains an enumerable dense set of points from which can be extracted a sequence having the lion as the limit. We then approach the lion stealthily along this sequence bearing with us suitable equipment.
3) The Dirac method: We observe that wild lions are ipso facto not observable in the Sahara desert. Consequently if there are any lions in the Sahara, they are tame. The capture of a tame lion is left as an exercise for the reader.
4) The thermodynamic method: We construct a semi-permeable membrane which is permeable to everything except lions and sweep it across the Sahara.
5) The Kalra method: Make a list of the lion's whereabouts. Classify them into different fuzzy sets. The lion will get confused and fall into your trap.
6) Topological method: We observe that the lion has at least the connectivity of the torus. We transport the desert into four-space. It is then possible to carry out such a transformation that the lion can be returned to 3-space in a knotted condition. He is then helpless.
{Note: this also works on Rob Stevenson.}
7) The Schrodinger method: At any given moment there is a positive probability that there is a lion in the cage. Sit down and wait.
8) The Heisenberg method: You will disturb the lion when you observe it before capturing. So keep your eyes closed.
9) The Einstein method: Run in the direction opposite to that of the lion. The relative velocity makes the lion run faster and hence he feels heavier and gets tired.
10) The Newtonian method: Let the lion catch you (let's assume you remain alive here). For every action there is an equal and opposite reaction. Therefore, you would have captured the lion.
11) The cartesian method: Take the origin as close as possible to the lion. Then perform rotation operation again and again. Initially, the lion will feel dizzy. Finally it will fall down.
12) The software method: Make a linked list of all objects in the desert. Then delete the pointers on either side of the lion. (Make sure you are not AFTER the lion.)
13) The automata method: Use a Non-Deterministic Finite Automaton with epsilon moves from all states to the final state, and no moves from the final state. The lion will soon enter the final state and be trapped.
14) The time-cop method: Use a time-machine and take the entire Sahara back a few years in time. The lion is just a cub now, and all you need is a mouse-trap.
15) The integro-differential method: Integrate the Sahara over its entire surface. The lion is now somewhere in the result. Differentiate the result w.r.t. the earth's rotation. The resulting value is zero, and the lion is no more.
16) The Shakespeare method: Hold the lion still for a moment (I don't care how you do it), and recite Shakespeare`s Hamlet to it. The lion will change from 'To be to Not-to-be'.
17) The Unix method: Put the lion on (the hard) disk. Do : ls -l | grep -i "lion" | cut $9 > trapfile. The “-i” option ensures that size of the lion does not matter. Now the lion is caught in a trapfile, and can be safely tar-ed or backed up into tape !
18) The Quantum Measurement Method: We assume that the sex of the lion is _ab initio_ indeterminate. The wave function for the lion is hence a superposition of the gender eigenstate for a lion and that for a lioness. We lay these eigenstates out flat on the ground and orthogonal to each other. Since the (male) lion has a distinctive mane, the measurement of sex can safely be made from a distance, using binoculars. The lion then collapses into one of the eigenstates, which is rolled up and placed inside the cage.
19) The nuclear physics method: Insert a tame lion into the cage and apply a Majorana exchange operator 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, exchanging spins.
20) The Newton method (II): Cage and lion attract each other with the gravitation force. We neglect the friction. This way the lion will arrive sooner or later in the cage.
21) The Special relativistic method: One moves over the desert with light velocity. The relativistic length contraction makes the lion flat as paper. One takes it, rolls it up and puts a rubber band around the lion.
22) The general 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.
23) The Darwin method: Put amoeba in a glass of water in a cage. Sooner or later, the amoeba will evolve into a lion.
24) The Heisenberg method (II): Position and Velocity from a moving lion can not be measure at the same time. As moving lions have no physical meaningfull position in the desert, one can not catch them. The lion hunt can therefore be limited to resting lions. The catching of a resting, not moving lion is left as an exercise for the reader.
25) The atomic fission method: We irradiate the desert with slow neutrons. The lion becomes radioactive and starts to disintegrate. Once the disintegration process is progressed far enough the lion will be unable to resist.
26) 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.
27) The Hilbert (axiomatic) method: 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.
28) The projective geometry method: 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 interiour point of the cage. Thereby the lion is mapped onto that same point.
29) The Bolzano-Weierstrass method: Divide the desert by a line running from north to south. The lion is then either in the eastern or in the western part. Let's 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. Let's 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.
30) The Peano method: 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. ([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)
31) The search method: We assume that the lion is most likely to be found in the direction to the north of the point where we are standing. Therefore the REAL problem we have is that of speed, since we are only using a PC to solve the problem.
32) The parallel search method: By using parallelism we will be able to search in the direction to the north much faster than earlier.
33) The Monte-Carlo method: We pick a random number indexing the space we search. By excluding neighboring points in the search, we can drastically reduce the number of points we need to consider. The lion will according to probability appear sooner or later.
34) The practical approach: We see a rabbit very close to us. Since it is already dead, it is particularly easy to catch. We therefore catch it and call it a lion.
35) The common language approach: If only everyone used ADA/Common Lisp/Prolog, this problem would be trivial to solve.
36) Linear search: Stand in the top left hand corner of the Sahara Desert. Take one step east. Repeat until you have found the lion, or you reach the right hand edge. If you reach the right hand edge, take one step southwards, and proceed towards the left hand edge. When you finally reach the lion, put it the cage. If the lion should happen to eat you before you manage to get it in the cage, press the reset button, and try again.
37) Mathematicians hunt lions by going to Africa, throwing out everything that is not a lion, and catching one of whatever is left. Professors of mathematics prove the existence of at least one lion and leave the capture of an actual lion as an exercise for one of their graduate students.
38) Computer scientists hunt lions using algorithm A: 1. Go to Africa, 2. Start at the Cape of Good Hope, 3. Work northward in an orderly manner, traversing the continent alternately East and West. 4. During each traverse a. Catch each animal seen, b. Compare each animal caught to a known lion, c. Stop when a match is detected. Experienced computer programmers modify Algorithm A by placing a known lion in Cairo to ensure that the algorithm
will terminate.
39) Engineers hunt lions by going to Africa, catching yellow animals at random, and stopping when any one of them weighs within plus or minus 15 percent of any previously observed lion.
40) Economists don't hunt lions, but they believe that if lions are paid enough they will hunt themselves.
41) Statisticians hunt the first animal they see N times and call it an lion.
42) Consultants don't hunt lions, but they can be hired by the hour to advise those who do. Operations research consultants can measure the correlation of hat size and bullet color to the efficiency of lion hunting strategies, if someone else will identify the lions.
43) Politicians don't hunt lions, but they will share the lions you catch with the people who voted for them.
44) Lawyers don't hunt lions, but they do follow the herds around arguing about who owns the droppings. Software lawyers will claim that they own an entire herd based on the look and feel of one dropping.
45) When the Vice President of R&D tries to hunt lions, his staff will try to ensure that all lions are completely prehunted before he sees them. If the VP sees a nonprehunted lion, the staff will (1) Compliment the vice president's keen eyesight and (2) enlarge itself to prevent any recurrence.
46) Senior managers set broad lion hunting policy based on the assumption that lions are just like field mice, but with deeper voices.
47) Quality assurance inspectors ignore the lions and look for mistakes the other hunters made when they were packing the jeep.
48) Salespeople don't hunt lions but spend their time selling lions they haven't caught, for delivery two days before the season opens. Software salespeople ship the first thing they catch and write up an invoice for an lion. Hardware salespeople catch rabbits, paint them yellow and sell them as "desktop lions."
49) Surgical method: A lion may be regarded as an orientable three-manifold with a nonempty boundary. It is known that by means of a sequence of surgical operations (known as 'spherical modifications' in medical parlance) the lion can be rendered contractible. He may then be signed to a contract with Barnum and Bailey.
50) Logical method: A lion is a continuum. According to Cohen's theorem he is undecidable (especially when he must make choices). Let two men approach him simultaneously. The lion, unable to decide upon which man to attack, is then easily captured.
51) Functorial method: A lion is not dangerous unless he is somewhat gory. Thus the lion is a category. If he is a small category then he is a kittygory and certainly not to be feared. Thus we may assume, without loss of generality, that he is a proper class. But then he is not a member of the universe and is certainly not of any concern to us.
52) Covering space method: Cover the lion by his simply connected covering space. In effect this decks the lion. Grab him while he is down.
53) Game theoretic method: A lion is big game. Thus, a fortiori, he is a game. Therefore there exists an optimal strategy. Follow it.
54) Group theoretic method: If there are an even number of lions in the Sahara Desert we add a tame lion. Thus we may assume that the group of Sahara lions is of odd order. This renders the situation capable of solution according to the work of Thompson and Feit.
55) Biological method: Obtain a number of planarians and subject them to repeated recorded statements saying: 'You are a planarian'. The worms should shortly learn this fact since they must have some suspicions to this effect to start with. Now feed the worms to the lion in question. The knowledge of the planarians is then transferred to the lion. The lion, now thinking that he is a planarian, will proceed to subdivide. This process, while natural for the planarian, is disastrous to the lion.
56) Mittag-Leffler method: The number of lions in the Sahara Desert is finite, so the collection of such lions has no cluster point. Use Mittag-Leffler's theorem to construct a meromorphic function with a pole at each lion. Being a tropical animal a lion will freeze if placed at a pole, and may then be easily taken.
57) Method of natural functions: The lion, having spent his life under the Sahara sun, will surely have a tan. Induce him to lie on his back; he can then, by virtue of his reciprocal tan, be cot.
58) Boundary value method: As Dr. Morphy has pointed out, Brouwer's theorem on the invariance of domain makes the location of the hunt irrelevant. The present method is designed for use in North America. Assemble the requisite equipment in Kentucky, and await inclement weather. Catching the lion then readily becomes a Storm-Louisville problem.
59) Method of moral philosophy: Construct a corral in the Sahara and wait until autumn. At that time the corral will contain a large number of lions, for it is well known that a pride cometh before the fall.
60) The psychiatric method: Prescribe a drug such as Prozac to it. Upon taking this drug, it will have no emotional stimulus on which to react, thus causing it to return for further counselling.
61) The inductive method: Initial Condition: If you center a large cage on any one grain of sand, and a lion is on or close to the grain of sand. then he will be trapped by the cage. By close we mean within epsilon grains of sand. Given a cage the size of 2 * (size of lion * epsilon) it works. First Hypothesis: Given the first grain of sand in the desert, if the lion is standing on it you will trap him. Proof: Given by the initial condition. Induction Hypothesis: Assume that a lion is on a grain of sand n, and is trappable. Now, for grain n+1 (assume all grains of sand are ordered, inorder) n+1 is close to n, hence n is close to n+1. If the lion is on grain n, and is trappable; then he is close to n+1, and by the above condition, trappable. Hence, no matter where the lions are if you drop a cage centered on a piece of sand you will catch a lion.
62) The divide and conquer method (by recursion): Divide the desert in half. Repeat the process until you have the lion, a grain of sand, or some other object that cannot be divided without blood shed. You have the lion. The order of this method = O(insane). (Where sanity is anything reasonable.)
63) The square method: Square Sahara. Somewhere you will get a square lion. If the lion was negative, it will now be positive, which makes catching it a whole lot easier. (The actual catch is left as an exercise for the reader). Put lion in cage. Draw square root. If you prefer to have a negative lion, change signs. Warning: Do not draw square root of lions not already squared and put in a cage. If the lion was not square, it will become irrational. And if the lion was negative, you will start seeing imaginary lions.
64) The Bill Gates method: Convince Bill Gates that lions are important. Then he will put a lion in your next Windows. Therefore you will have a lion, even already framed.
65) The George W Bush method: Bomb (… somewhere). Then nobody will remember that you were supposed to catch a lion.
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