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Q.E.D., vol. 47, by Katou Motohiro. Grade: B
----- Spoilers -----
(Gidel plays while Rome burns; talking about the P vs NP problem.)
Hi wa Mada Takai (The Sun is Still High Up, Monthly Shonen Magajin Plus 07, 2013).
The story starts out with a patrol car chasing after a speeder, when the other driver wipes out and his car crashes. The scene shifts to the police station in Bali, with Kurt Gidel and Mutiala being asked for help. Turns out that the speeder was found to possess a notebook reported by Mutiala to have been stolen from Kurt, but it was charred to a crisp in the car fire. Mutiala is getting frustrated at Kurt's lack of concern, and he makes things worse by saying that by following the logic, he himself is the main suspect. Finally, Mutiala contacts a friend of hers from MIT, Eva, for help. Eva talks to Loki, and the two of them go to Bali and tell Touma and Kana to meet them there. We now learn that Kurt Gidel (a play on Kurt Godel) is a genius mathematician working for the American NSA to try to crack the traveling salesman problem. It's an NP-hard class problem, where the idea is, given a group of cities scattered around a map, find the shortest path for the salesman to take where he visits each city only once. This computer task is part of the P vs NP problem that remains unsolved, and for which the Clay Institute is offering a $1 million prize (along with the Riemann Hypothesis). The issue is that by adding one more city to the map, the number of calculations increases geometrically instead of linearly. By cracking P vs NP, the NSA would be able to decipher computer passwords more easily as part of its spying activities. Gidel had demanded to work in a relaxing setting in a heavily guarded cottage in Bali, and Mutiala is not only his personal secretary, but also a direct report to the NSA offices in the States. Which is why she's so upset that Gidel is more interested in playing bongos in a party with the natives than in finding out who stole his notes.
(Judith describes Gidel's almost-magic-like ability to turn a raw idea into a polished logical diamond.)
The full staff at the cottage consists of Gidel, Mutiala, programmer Carlos Balma, logician Walter Chapman, mathematician Judith Gray, and at least 10 guards. On the day in question, the main group met in Gidel's office to discuss theories as normal. Gidel's notebook was placed on a blackboard chalk holder, as normal. Walter had arrived late because he had to report his security card missing and couldn't get past the locked front door until he obtained a temporary replacement, so he was unprepared in his presentation. Judith left the room to go to the kitchen to make coffee, but the filter tore and blocked the top of the drip pot, making a mess all over the floor that she had to clean up. When she returned to the room, Carlos had gotten involved in Walter's discussion and filled the blackboard with drawings. However, none of it was worth Gidel's writing comments into his notebook. At the end of the day, Gidel returned the notebook to its shelf, everyone else's notes were shredded, but the shredder jammed and Carlos had to fix it, then everyone left the room, and Gidel himself locked the door behind them. All of them were given a full body search by the guards on their way out. A little later, because Judith had left the room to make coffee without a pat down, Mutalia got suspicious and went back to look at the notebook, where she discovered that it had been replaced with a blank book. She ran to the communications room and contacted NSA HQ, and they found a message from a net cafe in town indicating that an information broker had paid $50K for the book, and the police were notified. However, both people were wearing masks during the sale, so the suspects from the car crash can't finger the thief. And every time someone asks about the case, Gidel either adds to the list of suspects, or tells people to look up at the stars, instead. The notebook was generally next to Gidel all the time, so he had access, but no motive. Walter's mother is in the hospital and he needs money, so he has motive, and he claims his girlfriend got angry and threw his wallet with the security card into the ocean, so maybe he'd entered the cottage earlier to plant a fake notebook, but didn't want his card to show up in the records twice in 20 minutes. Judith could have tried smuggling the notes out and hidden them in the kitchen sink drain pipe for a guard to recover, but she's lacking motive. Mutiala could have made the sale herself, but she doesn't need the money. And, Carlos has a gambling problem, betting on cock fights, but he didn't have access to the notebook. Questions: Who stole the notebook, and how? Why is Gidel so unconcerned and constantly suggesting new motives or methods? Was the theft conducted as part of a terrorist plot, a need for money, or something else?
(Walter tells Touma about Carlos' gambling problem, and how the notebook was always next to Gidel.)
----- Spoilers -----
Touma's first point is to remind everyone that this case is exactly like the traveling salesman problem. By adding a new suspect, the amount of work to show that the suspect is innocent increases geometrically. It doesn't make the problem unsolvable, it just takes much, much longer to get an answer. This implies that Gidel knows who the thief is and is covering for them. The key is that there are two blackboards, one in front of the other on guide rails. When the first board is covered in notes, it can be raised to let you write on the next one. The suspect had smuggled in the fake notebook before the meeting started and put it behind the front blackboard roughly where Gidel normally set the real one everyday. He also tore the top paper coffee filter in the pack so it would provide a distraction when it ripped open. Then, after Walter spent time fruitlessly explaining his theory, the suspect stood up to participate in the discussion to fill the front blackboard with notes. When Judith reentered the room after cleaning the kitchen floor, the suspect used the distraction to raise the front board, lifting up the real notebook and revealing the fake one in back. Later, during clean up, the suspect deliberately fed too much paper into the shredder to jam it so he could sneak the notebook into the trashbag. That evening, he stole the shred bag to take the notebook out before it could be burned. Unmasked, Carlos breaks down, saying that he just wanted to be recognized for his ideas, since his theories were in that notebook, too. At the end, Gidel congratulates Touma on his "beautiful deduction". He says that the NSA has decided to recall him to work in a lab in the States, so he'll just have to build a new team and start over. Then, a group of kids playing soccer on the beach complain that the sun's going down so they have to give up and go home now. Gidel runs over, grabs the ball, and says, "What are you talking about? The sun's still high in the sky" and he plays with them during the remaining 20 minutes before the sun fully disappears behind the horizon.
Science: Touma and Loki describe the "P vs NP" problem, and how adding one more point to the map causes the amount of time to find a solution to go up nonlinearly. Note that while "Kurt Gidel" is a play on "Kurt Godel", the mathematician and logician, the character acts more like playful physicist Richard Feynman.
(Aki recalls having only one friend in junior high.)
Sakamichi (Hill Road, New Work for this Volume, 2014).
The story starts out with a young junior high school student, Aki Utagawa, remembering how everyone had treated her like trash in school. She'd tried asking a boy out, but he'd turned her down. At the depth of her depression, one girl approached her to be on the basketball team (because of her height). When some of the other boys made fun of the new girl, she crushed them under a desk, asking them why they felt compelled to comment on other people's conversations. The two became friends, but before graduating from juniour high, Aki's parents got divorced and her mother took her with to a small fishing village. A few years later, the class is reuniting for a party, and Aki comes back to Tokyo specifically to meet her friend again. One of the guys, Hideki Tajima, discovers that Aki is a popular, beautiful model now and wants to hit on her. But, before he can act, Aki's friend shows up - Kana. Some of the former class go to a family restaurant, where Aki asks Kana if she remembers the "video game incident". At the time, one of the boys had brought in a new video game he'd bought to show to his friends, but the teacher entered the room and the kid hid the game in his bag. Later, the kid claimed that the game was missing, and it turned up in a search of the desks; specifically, in Aki's desk. Everyone else started accusing Aki of being a thief, but Kana stood up for her, saying that Aki was innocent, but she was unable to tell the teacher who the real thief was. Aki now asks Kana if she remembers the incident, and she can't.
(Aki is popular now, so finally her former classmate, Hideki Tajima, wants to date her.)
As the story progresses, we learn that Aki had only posed for one fashion shoot, and one of the photos had gone viral. She's now working with an agent to explore a career as a professional model, involving a trip to Paris, but she's lacking self-confidence. Unless Kana can remember the "video game incident", Aki can't move forward on her own. After the reunion, Aki returns to her mother's home in the fishing village, and she invites some of the other female former classmates to visit her. That night, as Aki starts preparing meat for dinner, she realizes that she forgot the marinade. She runs out to the convenience store. Then, the ladder to the apartment on the second floor of the building falls over. Kana jumps down to replace the ladder, and when the girls reenter Aki's room, they discover that the envelope with Aki's mother's $500 for rent and expenses is missing. The girls panic and try to find the money, but Aki is spied coming up the back hill road, and eventually they have to apologize over the missing money. Kana calls Touma demanding help, and he tells her to look in places where the envelope couldn't have been expected to fall behind. Kana asks Aki if she can look in the room a little more, and she says that she has to work with her mother for an hour and to go ahead. Pretty quickly, Kana finds the money in one of Aki's junior high school yearbooks. Questions: Who took the money and why? Why is Aki so wrapped up in getting Kana to remember the video game incident? Will Aki's lack of confidence torpedo her modeling career?
(Kana defends Aki, but can't explain why the other girl is innocent.)
----- Spoilers -----
Touma comes out to the village and does a little scouting before joining everyone from the meat party at Aki's apartment. He states that he'd just verified that this village doesn't have a convenience store, and all of the food shops close early. Therefore, the suspect had bought the marinade in advance and left it outside the apartment. When she left to get the marinade, she knocked the ladder over from the roof and entered the bedroom through the window while the others were trying to put the ladder back. She hid the money in the yearbook (she'd claimed she never kept the yearbooks herself) and then walked down a wall so that the girls would see her and think she was coming back early. In fact, the streets here are too low down and can't be seen from Aki's bedroom. Pretty obviously, the culprit is Aki herself. The motive is to try to get Kana to explain herself. Kana still can't figure out why this is so important, until Touma tells her that her refusal to tell the teacher who had stolen the video game means that Kana herself had done it and put the game in Aki's desk. This is why Aki is so desperate to know if she can trust her spiritual pillar - Kana. Kana berates herself for not seeing the obvious, and explains that on the day in question, she'd overheard Aki trying to ask someone out, and had witnessed her being turned down. Concerned, Kana had followed Aki around during the lunch break and had returned to the room just as Aki was being accused of being the thief. Having stalked Aki, Kana knew that she was innocent but didn't want to say why, and she'd never seen the theft take place. Touma then reveals the real culprit of the "video game incident - the kid that had brought the video game to school didn't want to be caught with it when the teacher came in. The kid was also the one that Aki had tried asking out, so he wanted to embarrass her by putting the game in her desk. Additionally, the kid's name is Hideki Tajima, the same Hideki Tajima who was going to try hitting on Aki at the class reunion after finding out that she'd become a model. Things wrap up with Aki going to Paris to start her career. She mentions that she'd gotten a letter from Kana saying, "The enemy has been punished, you can rest easy now," but she has no idea what it means.
Comments: The Sun is Still High Up is a pretty good mystery, and I like Gidel and the parts about the traveling salesman problem. The motive is weak, though, although the setting itself is very topical. It's a little hard to believe that someone who signed over all of his intellectual property before starting a government job contract would get that upset at not being able to claim credit for it. Hill Road is pure fluff, and Aki comes off as very emotionally unstable. Her behavior seems irrational until her final suspicions of Kana are revealed, so it wasn't that much fun of a read. I recommend this volume mainly if you like logic problems.