The autumn colors are charming, and the seven bridges that have just been built in the southern suburbs of the holy city attract tourists. Pen Fun Pavilion wWw. ｂiquge。 ｉｎfo

The grassy slope on the shore is full of horse-drawn carriages, in the garden on the island in the middle of the river, young people stand under the fallen leaves of the orchid trees, and if the visitors walking on the bridge frown and meditate on the warm blue jade bridge railing, they are probably thinking about how to solve the problem of the "Darwinian labyrinth".

More people gathered on the banks of the river, around three huge stone monuments, to judge their heads.

The vast majority of those who have leisure to enjoy the scenery or want to challenge the three bounty puzzles are Hailian people living in St. Petersburg.

However, there are exceptions.

At a distance from a certain stone monument, two plainly dressed Madtims stood side by side, probably because they knew that they were lowly, so they consciously avoided the noble Helians.

Both of them were of some age, and it was evident from the sun-tanned complexion that they had been working outdoors all year round, and the older one seemed to have some inconvenience on his legs and feet, but the expression on his face was very excited, while the other looked at the stone tablet from a distance and wiped tears from the corners of his eyes.

......

The small building of the Superintendent's Society, which has been lost for a long time, is still cramped and gloomy.

But even if the little building was dilapidated, President Grantis was stingy, Master Vincent was a philistine, and Miss Nancy's hair was like it hadn't been washed in months...... Donner, however, still thinks it's very humane. It was something he hadn't seen anywhere else in the Magic Continent.

Maybe it's because everyone here has given up on the pursuit of power. Donner thinks so.

A few months ago, Donner would hide in his own small room every morning to draw magic circles, but now, after becoming a genius in everyone's mouth, he didn't do it.

The reason is simple, although he can draw an astonishing circle at any time, any one of them may bring attention that he does not want.

He knew that the Silence Circle was already the limit. This sixth-level magic array, which is very similar to the soundproof magic array, can be dismissed as a coincidence, but since it is a coincidence, it is impossible for it to happen one after another.

In contrast, it is more rational to solve the problem of the Seven Bridges and get the first bounty.

Because once this question is solved, everyone will find that the answer is not complicated at all. Correspondingly, solving this puzzle attracts much less attention than discovering a new magic circle - you know, in the more than 10,000 years since the establishment of the Magic Circle Association, no one has discovered a new magic circle except Donner.

Still, Donner wasn't ready to do it right away. After all, the Seven Bridges have just been completed, and if he comes up with the answer now, he may be seen by President Grantis that he is playing tricks.

So, on the first day after returning to the Inspectorate, Donner found that he had nothing to do.

In this rare free time, he began to carefully consider his plans for returning to Middle-earth, and then suddenly thought of something he had received from Natia Vida when he was on the continent of Huls.

Rank 9 magic crossbow.

He clearly remembered that even ordinary people could use that kind of magic crossbow.

According to the knowledge he obtained in the Magic Continent, any magic array above level 6 is a beast core array, and they can only be used by magicians of the corresponding level - the magic wand is a kind of beast core array.

Then, there is only one possibility: Natia's so-called ninth-level magic crossbow is not a ninth-level beast core magic circle at all, but a combination of multiple magic crystal magic arrays.

After Donner became a full member of the Magic Array Association, he had seen a magic scroll that could fire guiding crossbow arrows in the magic array manual, and it was conceivable that the so-called ninth-level magic crossbow that was completely enclosed was most likely a war weapon made by the magic array workshop, and was captured by the dwarves in the war three thousand years ago.

The reason why this magic crossbow is recognized by the dwarves as a ninth-level magic circle may be because the magic continent said this when they distributed them to the Middle-earth army during the war, or it may be that the dwarves evaluated them according to their power.

In any case, since no new offensive magic arrays have appeared in the past three thousand years, this magic weapon will most likely still be the protagonist on the battlefield in the coming war.

Thinking that he had easily annihilated the tens of thousands of troops of the Thorn Empire with his improved and weakened magic crossbow, Donner couldn't help but have a headache.

How to deal with this magic crossbow should be one of the most important issues for him to consider after returning to Middle-earth.

In addition to this, he needs an army of qualified magicians.

This question was actually already in front of him right now - Una and Layla had been so devoted to learning magic array drawing that they didn't have time to practice building magic models, and even if Donner had prepared a seventh-level magic potion for them, they wouldn't be able to improve to the corresponding combat power without mastering the magic model.

One way to solve this problem quickly is to use the biochip on the Jingwei.

But Downer didn't want to do that.

On the one hand, he didn't want Una and the others to know about the existence of the Jingwei, and on the other hand, after knowing that the Doctor might have something to hide from the Jingwei, he didn't dare to fully trust the Jingwei.

So, he chose a more complicated, but safer method - simplifying the magic model, and then taught Una and Layla the simplified magic model.

As long as this can be done, then the future army of magicians can be concocted in the same way.

In fact, shortly after arriving in the Magic Continent a year ago, Donner had tried to simplify the magic model. At that time, he had looked through many books on magic models, trying to find a way to find a new way, but those efforts had not yielded results.

Now the situation is different. With the help of the brain, Donner only needs to provide ideas, and all the calculations and experiments can be completed by the brain.

Donner has had the idea for a long time, and this idea has something to do with the Seven Bridges problem.

In topology, there is a well-known conjecture -- in the Downer's mind, it seems to have been proven and can be called a theorem.

The theorem is as follows: any single-connected, closed n-dimensional manifold must be homogeneous to an n-dimensional sphere.

Okay, Poincaré's theorem is a bit hard to understand, but Donner only needs to use a subset of it, and it's a custom version for a simplified magic model:

"A three-dimensional spherical magic model can be transformed into other closed shapes, and by exhausting these closed shapes, one can always be found that is easy to understand and easy to construct. The second half of the sentence was added by Donner himself, because Poincaré had not studied magic models, so it was impossible to draw such a conclusion. And the so-called ease of understanding and easy construction is really a not very objective description, and no serious mathematician would say such a thing.

That said, considering that the second half of this conjecture is crucial to the wizarding world in which Donner lives today, let's recognize its value and call it the Venn conjecture.

(Ask for a monthly pass!Ask for a recommended ticket!) (To be continued.) )