Beach Bridge, Krämerbrücke
Green Bridge, Grünebrücke
Drochy (working) bridge, Koettel Brücke
Blacksmith Bridge, SchmitderBrüke
Wooden Bridge, Holzbrücke
High Bridge, Hohebrücke
Honey Bridge, Honigbrücke
From a long time, the inhabitants of Königsberg beat over the mystery: can we go through all the bridges of Koenigsberg, passing for everyone only once? This task was solved and theoretically, on paper, and in practice, for walks - passing through these most bridges. No one managed to prove that this is impracticable, but also no one could make such a "mysterious" walk through the bridges.
In 1736, a famous mathematician, a member of the St. Petersburg Academy of Sciences Leonard Euler, took to solve the task of seven bridges. In the same year, he wrote about this engineer and mathematics Marioni. Euler wrote that he found a rule by which it is easy to calculate whether it is possible to go through all the bridges and at the same time do not go through one by one. At seven bridges of Königsberg make it impossible.
It is thanks to this task about bridges on the map of Old Koenigsberg, another bridge appeared, with which the island of Lomme with the south side was connected. This happened in this way. The emperor (Kaiser) Wilhelm was known for simplicity of thinking, rapidly reaction and soldier "non-smile." At one of the techniques where the Kaiser was present, invited scholar minds decided to play a joke to play: Wilhelm had shown the map of Königsberg, offering to solve the task of bridges. The task is obviously unreserved. Wilhelm, to the general surprise, demanded a feather and paper, stating that the task is solvable and he will solve it in a matter of minutes. Found paper and ink, although no one could believe that Kaiser Wilhelm has a solution to this task. On the Caisser's submitted paper sheet wrote: "I order to build an eighth bridge on the island of Lomme." The new bridge was called the Imperial Bridge or Kaiser-Brucke.
This eighth bridge made the task of bridges of light fun even for a child .... 
Dear hors, personnel ...
There is a famous mathematician, a member of academies, probably a professor or even Academician Euler, and there is just Kaiser Wilhelm. Euler decided that it was impossible to solve the task, the Wilhelm had an affordable way that it was not. I am sometimes disputes with you resemble the above-mentioned textbook example.
Well, I do not want that I would have worked with this this citizen more.
Because she turned out to be a bad employee.
But we can not dismiss her ...
And why is that?
So after all ... the article is so, section, paragraph, paragraph ...
I need a worker, not an article!
Read the labor legislation ...
I read. I call himself and he firing himself. And I understand that most of you will remain at the level of "Article such, section, paragraph, paragraph ..."
Unconventional solutions to the problem
"Decision" Kaiser
On the map of Old Konigsberg there was another bridge, which appeared a little later and connected the island of Lomze with the south side. This bridge is obliged by the very task of Euler-Kant. This happened under the following circumstances.
The emperor Wilhegelm was known for his directness, simplicity of thinking and soldier's "inconsistency". Once, being in a secular round, he almost became a victim of a joke, which he decided to play the minds present at the reception. They showed a kaiser Konigsberg card, and asked to try to solve this famous task, which by definition was unreserved. To universal surprise, Kaiser asked the feather and a sheet of paper, saying that he would solve the task over a minute and a half. The stunned German establishment could not believe his ears, but the paper and ink quickly found.
Kaiser put a piece on the table, took the pen and wrote the following: "I order to build the eighth bridge on the island of Lomme." So in Königsberg and a new bridge appeared, which was called the Kaiser Bridge. A task with eight bridges could now solve even a child.
see also
Literature
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7 bridges of the city of Kaliningrad (Keningsberg) led to the creation of the so-called theory of graphs by Leonard Euler.
The graph is a specific number of nodes (vertices), which are connected by ribs. Two islands and shores on the Pregel River, where it stood, 7 bridges were connected. The famous philosopher and scientist I. Kant, walking along the bridges of Königsberg, came up with a task that is known to all in the world as the task of "about 7 Kenigsberg Bridges": can we go through all this bridges and at the same time return to the starting point of the route so as to go through Each bridge only once?
Many tried to solve this task both practically and theoretically. But no one did it. Therefore, it is believed that in the 17th century, the inhabitants had a special tradition: walking around the city, go through all the bridges only one time. But naturally, no one has succeeded.
In 1736, this task was interested in the scientist Leonard Euler, who was an outstanding and famous mathematician and a member of the St. Petersburg Academy of Science. It was able to find a rule, thanks to which it was possible to solve this riddle. In the course of his judgments, Euler made such conclusions: 1. The number of odd vertices (vertices to which the odor of the edge) of the graph should be even. There may not be a graph that would have an odd number of odd vertices. 2. If all the vertices of the graph are read, then you can, without taking a pencil from paper, draw the graph, while you can start from any vertex of the graph and complete it in the same vertex. 3. Count with more than 2 non-vertex vertices cannot be drawn by one stroke.
Hence the conclusion that it is impossible to go through all seven bridges, without passing one of them twice. Subsequently, this theory of graphs has become the basis for the design of communication and transport systems, has become widely used in programming, computer science, physics, chemistry and many other sciences and spheres.
It is noteworthy that historians believe that there is a person who solved this task that he was able to go through all the bridges only once, the truth is theoretically ....
And it was so. Kaiser (that is, the emperor) Wilhelm was famous for his simplicity of thinking, directness and "inconsistency." Once he almost became a victim of a joke, which scientists were played with him, showed a kaisar map of Konigsberg and asked him to try to solve this famous task, which was unresolved by definition. But Kaiser just asked the sheet and feather, while specifying that he would decide for only 1.5 minutes. Scientists were amazed - Wilhelm wrote: "I order to build the eighth bridge on the island of Lomme." That's all, the task is solved ... So in Kaliningrad and the new eighth bridge appeared across the river, named after Kaiser. And the task with eight bridges can solve the child ...
The father of the theory of graphs (as well as topologies) is Euler (1707-1782), which decided in 1736 the task, called the problem of Konigsberg bridges, is widely known at that time. In the city of Kenigsberg there were two islands connected by the seven bridges with the banks of the Pragol River and each other as shown in Figure 4.
The task was the following: Find the route of passing all four parts of the sushi, which began with any of them, it would end in the same part and exactly once passed on each bridge. Easy, of course, try to solve this task empirically, producing a bust of all routes, but all attempts will fail.
Figure 4- The task of Konigsberg bridges.
The exceptional contribution of Euler into solving this task is that he has proven the impossibility of such a route.
To prove that the task has no solution, Euler designated every part of the sushi with a point (vertex), and each bridge line (edge) connecting the corresponding points. It turned out a graph. The approval of the non-existence of a positive solution in this task is equivalent to an approval of the inability to bypass this graph in a special way.
Figure 5 - graph.
Elements of graph. Ways to set the graph. Subgraphs.
Such a structure as a graph in quality (synonyms is also used the term "network"), has a wide variety of applications in computer science.
GraphG. called the system (V., U.) ,
where V.={ v.} - many elements called verters graph;
U.=={ u.} - . number of elements called ribs graph.
Each edge is determined either a pair of vertices (V1, V2), or two opposite pairs (V1, V2) and (V2, V1).
If the edge of U is represented only by one pair (V1, V2) , It is called oriented Edgeleading from V1 in v2. In this case, V1 is called the beginning, and the V2 is the confinement of such a rib.
If the edge U is represented by two pairs (V1, V2) and (V2, V1), then u is called neoriented edge. Any non-oriented edge between the vertices V1 and V2 leads like V1 inv.2, So back. At the same time, the vertices V1 and V2 are both the principles and the ends of this rib. It is said that the rib leads like ofv.1 B.v.2, so I. ofv.2 B.v.1.
All two vertices that are connected by the edge are adjacent.
In the number of elements, the counts are divided into end and endless.
Count, all the Rib whose neoriented is called neorientedcount.
If the edge of the graph is determined by ordered pairs of vertices, then such a graph is called oriented.
R 
isook 6 - oriented graph.
Exist mixed graphsconsisting of both oriented and non-oriented Röbembers.
If two vertices are connected by two or more ribs, then these ribs are called parallel.
If the beginning and end of the edge coincide, then such a rib is called petle .
Countless loops and parallel Ryoebers are called simple.
If the edge is determined by the vertices v1 and v2, then edge incident V1 and V2 vertines.
Top, not incident in no edge, called isolated.
Top, incident smoothly one edge, and this is called this rib end or hanging.
Ribs that are put in line with the same pair of vertices are called multiple, or parallel.
Two the vertices of the ne-oriented graphv1 and V2 are called adjacent If the graph exists an edge (v1, v2).
Two vertices of oriented graph V1 and V2 are called adjacent If they are different and there is a rib leading from the vertex v1 in v2.
Consider some concepts for the oriented graph.
Figure 7 - oriented graph.
Simple way: 
Elemental path: 
Elementary contour: 
Circuit: 
For uni-oriented graphs The concepts of "simple way", "elementary path", "contour", "elementary contour" replace, respectively, the concepts of "chain", "simple chain", "cycle", "simple cycle". Count is called svyaznoyeIf there is a path (chain) connecting these vertices for any two vertices.
Un-oriented connected graph without cycles is called tree.
Uni-oriented incohered graph without cycles - forest.
Figure 8 - a connected graph.
Figure 9 -les.
Figure 10 - Tree.
The basics of the theory of graphs as mathematical science laid in 1736 by Leonard Euler, considering the task of Königsberg bridges. Today this task has become classic.
Former Königsberg (now Kaliningrad) is located on the Pregel River. Within the city of the river is washed by two islands. From the shores on the islands were thrown bridges. Old bridges are not survived, but the city map remained, where they are depicted. Koenigsberges offered to visit the following task: to go through all the bridges and return to the initial item, and on each bridge there should be only once.
The problem of seven Konigsberg bridges
The problem of seven Königsberg bridges or the task of Konigsberg bridges (it. Königsberger BrückenProblem) is an old mathematical task in which it was asked how to go through all seven Konigsberg bridges, without passing one of them twice. It was first solved in 1736 by the German and Russian mathematician Leonard Euler.
It has long been a mystery among the inhabitants of Königsberg: how to go through all the bridges (across the Pragol River), without passing one of them twice. Many Königsburshs tried to solve this task as a theoretically, and practically during walks. However, no one could prove or disprove the possibility of the existence of such a route.
In 1736, the task of seven bridges was interested in an outstanding mathematics, a member of the St. Petersburg Academy of Sciences Leonard Eilor, what he wrote in a letter to Italian mathematics and engineer Marioni on March 13, 1736. In this letter, Euler writes that he was able to find a rule, using which, it is easy to determine if it is possible to go through all the bridges, without passing twice in any of them. The answer was "impossible."
Solution of the task of Leonard Euler
At the simplified scheme of part of the city (column), bridges correspond to the line (arc graph), and the parts of the city are the lines connection points (the vertices of the graph). During the reasoning, Euler came to the following conclusions:
The number of odd vertices (vertices to which the odor number is conducted) of the graph should be well. There may not be a graph that would have an odd number of odd vertices.
If all the vertices of the graph are even, then you can, without taking the pencil from paper, draw the graph, while you can start from any vertex of the graph and complete it in the same vertex.
The graph with more than two odd vertices is impossible to draw in one stroke.
Count Königsberg bridges had four (blue) odd vertices (that is, everything), therefore, it is impossible to go through all the bridges, without passing one of them twice
Created by Euler, the theory of graphs found a very wide application in transport and communication systems (for example, to explore the systems themselves, the preparation of optimal routes of cargo delivery or data routing on the Internet).
Further history of Konigsberg bridges
In 1905, an imperial bridge was built, which was subsequently destroyed during the bombardment during World War II. There is a legend that this bridge was built by order of the Kaiser himself, who could not solve the task of Königsberg's bridges and became a victim of a joke that scientists who were present in the secular reception played (if adding the eighth bridge, then the task becomes soluble). On the supports of the imperial bridge in 2005, an anniversary bridge was built. At the moment, in Kaliningrad, seven bridges, and the graph, built on the basis of the islands and bridges of Kaliningrad, still has no Euler path.