Chapter 6: An Equation Full of Unknowns

Qi Yi held a photograph, standing on the pedestrian bridge in Southbank, Melbourne.

He was there to find someone, the person who had taken the photograph he was holding in his hands at that moment.

In a place like Melbourne Southbank, where high-rises jostled for space, it wasn't easy to figure out from a photograph where exactly, in which building and on which floor, the photographer had stood.

At this moment, although Qi Yi was studying a photograph, the problem he truly needed to face wasn't one of imagery, but rather one of statistics, or to be precise, a problem at the mathematical level.

Such a method of searching involved a significant amount of computation, and apart from that, success required specific conditions.

The photograph in his hands wasn't taken by Qi Yi himself, so he had no way to set the conditions in advance.

Qi Yi needed to use the knowledge he had acquired over the past four years in some of the world's most prestigious mathematics institutes and organizations to find someone he hadn't seen for four years, hadn't spoken to for five, who had long since disappeared from his life.

Mathematics is present in everyone's life, anybody who has been to school has learned math, but not many actually like it – you might not find even one in ten.

And even fewer people apply mathematical methods in their lives.

In other words, most people are not interested in applied mathematics – the general public would prefer math to be as far removed from them as possible.

But Qi Yi was not most people.

A year after Qi Yi was admitted to the Department of Probability and Statistics at the Peking University School of Mathematics, a professor at the Applied Mathematics Summer School replaced his graduate teaching assistant with Qi Yi.

To quote the professor, Qi Yi was born for applied mathematics.

Perhaps because Peking University has many extraordinary individuals, the Applied Math Summer School hosted there was not unpopular but actually quite sought-after.

However, for someone like Qi Yi, who had only just completed his freshman year, to become a teaching assistant was unprecedented.

It was also thanks to the professor's recommendation that Qi Yi secured an exchange spot to Stanford University in the USA in his sophomore year.

Qi Yi, in his search, now had to confront the tricky problem that Melbourne was an entirely foreign city to him, and the only thing he had to aid his search was the single photograph in his hands.

Consequently, the equation Qi Yi used in searching, brimming with unknowns, had extremely limited data and conditions available for solving the problem.

It was somewhat like the predicament of trying to make a meal with no rice.

Mathematics was Qi Yi's strength; he feared no amount of computational volume, only the possibility of an unsolvable equation.

If the multivariable equation proved unsolvable, Qi Yi would be unable to find the person he was looking for.

What brought Qi Yi to Melbourne to search was a piece of writing from three years ago.

The text helped Qi Yi understand why Yan Yan had suddenly broken up with him five years prior, during their senior year in high school.

Those words were meant to be a "letter" to him, but the writer chose not to send it, instead, turning it into an unpublished blog post.

...

Qi Yi and Yan Yan met in their first year of high school, fell in love in the second year, and didn't exchange a single word during the entire third year.

Starting a relationship in the second year – could that be considered early puppy love?

Qi Yi was the undisputed school hunk, while Yan Yan was...

Yan Yan was nothing special; she was just one of the inconspicuous individuals in the crowd.

"Inconspicuous" was, in fact, the highest praise that could be attributed to Yan Yan.

Before being inconspicuous, Yan Yan had a severe disposition that attracted negativity; she was unpopular.

To be precise, Yan Yan had always been targeted for some strange reason, subjected to bullying from a young age.

...

The opportunity for Qi Yi to see the words Yan Yan had written three years ago came from an email he received two weeks prior.

The sender had nothing to do with Qi Yi; strictly speaking, the sender wasn't even human – it was a machine.

The email came from the Microsoft MSN Spaces team.

The content had nothing to do with Qi Yi either.

It announced that MSN Spaces services would be shutting down completely in March of that year, and from the moment the email was received, users would no longer be able to post new entries in their MSN space.

The primary purpose of Microsoft sending out this email was to encourage users to "move house" for their digital space.

This was already the fourth email Qi Yi had received regarding this matter.

Microsoft was suggesting that MSN Spaces users migrate to the WordPress blogging platform under Automattic.

But WordPress's recognition in China was too low; two weeks prior, the fourth email offered information that domestic users could transfer their MSN Spaces to Sina Blog.

Sina's subsequent rise in the era of microblogging was, to some extent, due to this collaboration with Microsoft in the "migration project".

At that moment, aside from wondering for the fourth time why Microsoft would send him a moving email, Qi Yi felt nothing special about this email.

Qi Yi had never used MSN, nor had he ever blogged anywhere.

The news that MSN Spaces was discontinuing service and needed to be moved was completely unrelated to Qi Yi; it was as if it was none of his business.

When Qi Yi was a junior, he interned at Microsoft's Asia Research Institute; he was well aware that Microsoft wasn't the kind of company that would constantly send spam and harass users unrelated to its product.

One could overlook this happening once or twice, but upon receiving the "final ultimatum" for the fourth time, Qi Yi started to wonder if he had actually, at some point and somehow, registered for an MSN Space.

Qi Yi's Hotmail account was created when he was a high school junior and not yet broken up with Yan Yan; it was his only email account, and the only remaining connection between him and Yan Yan.

Five years ago, Yan Yan had asked for a breakup, returning all the "tangible" letters Qi Yi had written on paper over the previous year, and even asking for her own letters to him back.

Everything physically related to their relationship had been returned at Yan Yan's request—She didn't desire to be reminded of memories through objects.

However, the email account that Yan Yan registered for him with a combination of the pinyin of his name and the numbers of his birthday had no special significance.

Qi Yi had gotten used to this email account and had never bothered to change it.

When Yan Yan gave Qi Yi the account information, she said she'd register her own in a few days, so they could communicate via email, which wasn't as tiring as writing letters on paper.

But just a few days later, when Qi Yi was about to celebrate their "one-year anniversary of love," Yan Yan suddenly and inexplicably broke up with him without looking back.

Yan Yan's decisive request for separation deeply wounded Qi Yi.

However, since the breakup was already five years ago, Qi Yi could now recall that time with a bit more equanimity.

Qi Yi looked through his inbox—why did he keep receiving messages about MSN Spaces and the need to move?

After some thought, Qi Yi tried to log into MSN with his email account.

Then, Qi Yi discovered that he had indeed registered for MSN Spaces and even found a blog post he had written five years ago; it was his first and last blog post, which was actually just one sentence:

Ha ha~ Today I helped Grandpa register for a space~

Under this blog post, there was a comment written five years ago:

"Oh lalala, who registered? Really amazing~"

The person who left the comment was nicknamed "The Waiwai in Jiji Waiwai."

Five years prior, at the age of eighteen, only Yan Yan would have delightfully teased Qi Yi by calling him grandpa.

Qi Yi clicked on the space of the commenter, which also had sparse content, but compared to Qi Yi's, it was significantly richer.

There were three blog posts in total, two short and one long.

The first one was very brief, posted at the same time as Qi Yi's single entry from five years ago, and it also contained just one short sentence:

"I knew you'd click to see, oh lalala, of course, it was me, the amazing one~"

The second post was longer, published three years ago.

The third one had been posted less than a month ago and only had a few lines of text:

"Today I just moved to Southbank.

Then I received an email from MSN Spaces telling me to 'move.'

It turns out, 'moving' isn't something that only happens in real life.

But for a space that hasn't been visited by anyone in five years, it seems like there's nothing much I need to move away.

Maybe I won't move after all.

On the last day that I can still update my space, I'll pick up my camera and, with a picture of the view outside my window at this moment, say goodbye to my MSN Space.

Memories are always there, they can't be moved, can't be shifted."