Night fell. Song He carried a box of new oxygen bottles on his shoulder and hurried back to the dormitory.
The door to Dorm 102 next door stood wide open, and the smell of alcohol drifted out. The odor in the corridor was practically comparable to that of a brewery.
Song He put the oxygen bottles back in his dormitory, then turned around and went next door to find Xie Kefu.
Xie Kefu was hunched over his desk doing calculations. Green bottles of Tsingtao Beer covered the floor around his feet, probably bought from the School Supermarket.
"I've proved the beginning of the Sassoon Conjecture." Song He pulled out a sheet of paper, unfolded it, and laid it on the desk.
Xie Kefu was startled. He picked up the proof and glanced over it twice.
"What a coincidence!" He took out his own proof and placed it beside Song He's.
Comparing the two sheets, their progress was unexpectedly similar. Xie Kefu had written one or two more lines.
Song He looked slightly awkward and took back his proof. "Do you have any ideas for the next step?"
Xie Kefu shook his head repeatedly. "I've been stuck for half an hour. I've tried seven or eight approaches, but none of them worked! Weren't you studying the Calabi-Yau Theorem?"
"The Pikaqiu Theorem is too difficult. I can't chew through it in a short time, so I settled for something simpler." Song He smiled bitterly.
"Who would've thought the Sassoon Conjecture wouldn't be simple either, right?" Xie Kefu smiled bitterly as well.
Since both sides were at similar stages and neither had any ideas for the next step, there was nothing much to discuss.
Song He said goodbye and returned to the dormitory next door. Before leaving, Xie Kefu grabbed a bottle of