"No, I don't have any rivals," Shen Qi said.
"You've only got 10 points. The Calculation Princess has 20," Zhou Yu'an retorted.
"Math isn't for competing," Shen Qi said, shaking his head.
"Then why are you taking part in the math olympiad?" Zhou Yu'an asked.
"No particular reason. I go with the flow," Shen Qi said.
Zhou Yu'an: "I @￥*@!"
"Hey, Shen Qi, Zhou Yu'an, what are you two whispering about? Please observe the rules of Math Camp!" Sun Erxiong reminded them. Then he pointed at the projector screen. "Please look at Question Four."
Whoa.
The students below let out a strange sigh. What the heck was that?
The screen showed a bottle, a bottle made up of curved surfaces and curves.
Its long, slender neck twisted and stretched. Strangely, the bottle's body wasn't pierced, while its neck entered the bottle and joined up with the bottom.
The bottle had no inside or outside, and seemed impossible to exist in three-dimensional Euclidean space.
A sentence on the screen offered a hint: "The bottle is one-sided, and its first Betti number is 3; in other words, its genus is 1."
"You have one minute to understand this diagram," Sun Erxiong said.
All the students looked completely baffled, except Shen Qi.
One minute later, the projection switched to a new image.
The new image was a circle. There was nothing unusual about it; it was just the kind of circle people saw all the time, with its diameter marked by a dashed line inside.
"Listen carefully, everyone. I'll tell you that this surface is closed and has a Betti number of 1. What is its genus? You have one minute to think," Sun Erxiong said.
Sigh...
The students smiled wryly. This thing was so abstract—who the hell could understand it?
Swish!
Shen