"But speaking of which, ice cubes aren't cheap, can anyone here in Xicheng afford to spend them? If you can't sell it all at once, I'm afraid it will be difficult to put it until the next day. ”

Colin couldn't imagine how to sell ice water in a place where there was no refrigeration and insulation. Get a wooden box and cover a padded jacket?

"It's not expensive, so it's easy to sell."

With a hint of mystery in her smile, Anne explained:

"The Wizards Association in the Central District, I know the old man who guards the door at the back door, and I paid the price of fifty catties of charcoal a year in exchange for a job to help clean up the garbage every day.

"The salary is not much, but it has the advantage of being able to enter the place where magicians are trained, do you know how many ice cubes are produced every day by those magicians who practice frost magic? They left after practicing, and it was a waste to put so many ice cubes there to melt.

"So every time I go to clean up the garbage, I will smuggle some ice cubes back, and then sell them here, don't underestimate these, say it's not expensive, that's also compared to those exquisite beverage shops in the rich area, anyway, I have almost no cost, except for those who bribe the old man, I can earn dozens of silver guilders a year."

"I've thought about it, and when I get to buy a humble cart this summer, I'll be able to transport ice more efficiently, and then I'll make it possible for the whole street to drink ice water in the hot summer."

Anne said in the end, there was a faint momentum of wanting to cross her waist.

Colin was dumbfounded, he thought that Anne was a very funny girl, sometimes with a tendon in her head, and sometimes very changeable.

"Aren't you afraid of being discovered by the Wizards' Guild?"

"Just kidding, I'm super brave." Anne said vividly: "Besides, I don't steal anything valuable, and no one wants those ice cubes in the first place." ”

When she said this, she suddenly said a little embarrassed: "I'm really sorry, I've been talking about my business, and I almost forgot to get down to business." ”

"It's okay, I'm quite interested in these, not to mention it's still early." Colin looked around the surroundings and said, "But if you're here, will it delay your business?" ”

"No, there aren't many people who buy charcoal in the morning."

"Why?"

"Because the poor generally only use charcoal for heating at night, if they don't feel too cold during the day, they won't come to buy it, so sometimes when the day changes, many people will freeze to death." Anne said with some sadness but habitually.

On the issue of poverty, Colin of both generations had a very good say, but now is clearly not the time to talk about it, and he promptly diverted the subject:

"So let's get started?"

"Uh-huh." Anne immediately perked up.

Since the last time they agreed on the hill outside the city, the two have exchanged questions about the calculation of magic patterns since they went back, but although Anne is already smart, she still can't keep up with Colin's train of thought, so basically Anne is asking questions, and Colin is explaining.

In exchange, in addition to inspiring his own thinking in the discussions, Colin was able to gain a lot of knowledge and anecdotes about magicians and wizarding circles from Anne.

These are all things that Anne had helped a magician at the beginning, and the other party talked about it during her relationship, and it was because of this incident that she had the opportunity to be recommended to enter the Hall School of Magic, otherwise she would only rely on her to sell the two heavens of ice and fire, and I am afraid that she would not be able to save enough sponsorship money in this life.

The two sat on the floor at a low, tattered table in the shack, using stones to draw on the floor and table in place of pen and paper.

Half an hour later.

"The parallel problem of these two surface domains has finally been solved, thank you so much, Colin, if I had to think for myself, I am afraid I would not have figured it out before graduation."

Anne let out a sigh of relief, then moved her stiff muscles from holding one movement for a long time.

Colin said politely, and then asked with some confusion: "Speaking of which, why didn't you think that they would be parallel before?" As you can see, the final proof process, although a bit tedious, is not that difficult. ”

"It's hard enough, okay."

Anne couldn't agree with Colin, who was in the top three in theory for many years, but even so, it took several days of one-on-one instruction to understand the process.

To say that it's not difficult, doesn't it seem like you're stupid?

Colin was speechless for a while, his biggest problem now is the lack of a systematic understanding of magic theory, after all, what was taught in the academy during his apprenticeship was only the most basic things, not to mention the most cutting-edge and cutting-edge research, and even the topics that are popular in the wizard circle today, he can't touch it.

It's true that the talent is very strong.

But it is difficult for a good woman to cook without rice, and there is a limit to drawing inferences.

No matter how smart a person is, it is impossible to prove Fermat's theorem with only four operations.

Colin didn't know how to answer Annie, so he could only ask rhetorically: "If you find this difficult, then the following question about the regression count tending to the α surface domain should be more difficult, should you continue?" ”

"Go on!" Anne gritted her teeth.

Another half hour passed.

Anne looked down at the part of the proof that Colin had written, her brow furrowed, and she kept biting the nail of her index finger with her teeth.

"Honestly, Colin, I really can't agree with this paragraph, do we have a different understanding of Euburn's constant?"

"Don't consider this constant first, first substitute the trajectory of the semi-elliptic module into the set and compare it again, and you should be able to find that the induction method we have been using is actually going around the long road......"

"I still don't understand."

“……”

"Can the mapping relationship here be calculated without exhaustive methods?"

“……”

"I see, sure enough, my understanding of Euberne's constant is too superficial."

“……”

Anne was right, there was really no business in the morning, and for more than an hour, only one woman came to ask the price of charcoal, and in the end she didn't buy it, which made Anne, who was already a little irritable, even more angry.

"Thank you, Colin, for not fully understanding it, but I have gained something, at least for me to further confirm the correctness of your conclusions."

The back and forth, endless questions and explanations, made both sides feel very tired, and Anne was really embarrassed to continue asking, she still had a lot to digest today.

"Have you been doubting the conclusion?"

"It's hard not to be suspicious."

Anne rubbed her eyebrows: "In the positive value of the non-stretched mapping arc, there is an infinite pair of regression counts with a constant tendency to α surface, don't you think this conclusion is too absolute?" ”

"Is there one?" Colin disagreed: "Don't you think it's mathematically aesthetic?" ”

"What's so beautiful about this? It's awkward! And I get the feeling that once your conclusions are true, a lot of the theories of space magic will become ...... Even more awkward. ”

"Isn't that a bit of an exaggeration?" Colin was stunned.