Grant stood, his arms stretched overhead, the jacket, shirt, and trousers crisp on his body. His students stood again and hollered, their arms pumping. This time, applause did fill the space. He nodded to half the audience, pivot turned, then nodded to the other half. Disconcertingly, the applause seemed to be growing. They had to have noticed the jacket he wore now wasn’t the jacket he’d started with, but that didn’t stop anyone from cheering.

Duncan strode onto the runway to receive the applause as Grant left. The two passed each other. Grant glared. Letting this proof onto the runway was no accident. At the latest, the theorem house should have caught its flaws during the run through. Duncan trapped Grant in his arms. He whispered into Grant’s ear.

“Hi, Tsai.” Duncan always called Grant by his last name. “I know you’re angry at me. Meet me in the dressing room after the show. I’ll explain everything.”

Grant hung the proof of Gödel’s incompleteness theorem on a rack with the other proofs verified tonight. His own clothes lay in a heap on the dressing room table next to some proof that hadn’t been put away. His wallet and cellphone fell out as he pulled out his shirt. Wisps of thread jutted where there should have been buttons. One sleeve dangled from its seam. His trousers had been rent into strips. That explained how the stylists had undressed him so quickly. They’d assumed he’d worn a proof to the show and could fix the damage. His clothes, though, were just clothes, ready-to-wear.

The proof still on the table had an apology in Duncan’s handwriting pinned to it. Grant recognized the work, a proof of Fermat’s last theorem Duncan had created during grad school. Its asymmetrical curved seams emphasized Grant’s musculature. He didn’t feel clothed as much as he felt like an anatomy chart. Spent, he slumped into the chair next to the table and waited.

Duncan strode into the dressing room wearing the proof of the first significant problem they’d solved together: ten was a solitary number. A critical triumph, the proof never sold well. Too few people had the body to pull it off. Duncan had, and damn it, he still did.

To Grant’s dismay, Duncan wore the proof better now than ever. His brawn no longer fought to burst out of the proof. Rather, the proof now exposed his beautiful proportions. He was still the mutant spawn of the sun and lightning. If the sun had passed its zenith and the lightning was now the lament of distant thunder, he still made any room feel too cramped to contain him.

“You couldn’t have asked me for help before you put the proof on the runway?” Grant was determined to stay angry despite Duncan’s smile. “You invited Marc and Lisa here, all expenses paid. It’s not like you didn’t know how to find me.”

“You wouldn’t have come, much less helped, if I hadn’t brought your students here.” Duncan sat on the table. “The proof of Gödel’s incompleteness theorem is the signature piece of the fall collection. No one understood its flaw much less how to fix it. I brought here, the only way I could, the one person who could fix it.”

Grant stood. He folded his arms across his chest. With Duncan sitting on the table, they saw each other eye to eye. Duncan’s gaze burned, but Grant met it.

Duncan was right, as usual. Grant wasn’t above refusing to help just to spite him.

“The one person who could fix the proof? Give me a break. And what were you going to do if I’d failed or died trying? Let the fiasco destroy your theorem house?”

Buyers and editors were a fickle lot. One tumbling pass that wasn’t parallel to the sides of the runway was enough to cancel orders and deny publication.

“Like you could have failed.” Duncan shook his head. “I don’t risk my theorem house on just anyone.” He pulled out his cellphone, tapped at it, then handed it to Grant. “I’m about to offer the man in this video a job. Tell me what you think of him.”

The screen filled with a beefy guy jumping, spinning, and twisting up and down a runway. He used computability theory to prove Gödel’s incompleteness theorem, a corrected version of Duncan’s proof. The man reasoned with a strength and incisiveness that made Grant’s jaw drop.

Grant might quibble with the handful of moves that were not textbook perfect, but the result was superior to Grant’s attempt. He wanted Lisa and Marc to see this version.

“You should have gotten him to verify your proof tonight. If you already had this, why did you show the flawed proof?” Grant handed back the cellphone. “Never mind. I no longer have to understand or care about your machinations.”

Duncan stood. He bore down on Grant. His head and shoulders blocked the room from view. The musk and leather of his cologne enveloped Grant.

“Tsai, this is video from tonight. That’s you correcting my proof.” He held the phone in front of Grant’s eyes. “When I say you’re the one person who could fix the proof, it’s not flattery. As hard as you are on everyone else’s work, you’re even harder on your own. God knows how you sell yourself in interviews. Are you surprised you can’t find another job?”

Grant’s face burned. He pushed the phone away. His gaze fell to the floor as he sat.

“What makes you think I’m looking?” Grant slid the chair away from Duncan.

“Your department is eliminating its graduate program and some of its non-tenured faculty. Your student evaluations are . . . bi-modal. A small number of students will register for anything you teach. Everyone else writes comments like ‘Dr. Tsai can’t teach a cow how to moo.’ ”

Being a force of nature had its advantages. By the time Duncan had worked over the department’s administrators, they probably thought that Duncan was doing them a favor by letting them show him Grant’s evaluations.

“You used to be charming, Duncan.” Once, Grant would have done, hell, he had done anything Duncan wanted.

“I still am.” Duncan flashed a quick smile. “But you no longer trust me when I’m charming and I need you to work with me.”

“Yeah, right.” Grant forced himself to match Duncan’s gaze. “The first Duncan Banks collection got published in all the major journals and sold to all the major buyers. Everyone wanted to work with you. You didn’t need me anymore and I might as well not have existed.”

“You’re never going to forgive me.” Duncan seemed to deflate a little. “I’m not who I—”

“Make your damn offer.”

When the semester ended in a few months, Grant would be out of a job. Besides, his legs felt like marble. Otherwise, he’d have walked out.

“I have the outline of a solution for P=NP. Flesh it out with me. Please?”

Grant sighed. Whether P=NP was one of the remaining great unsolved problems. Proving that P=NP meant biologists could quickly compute the structure of a protein rather than guessing its structure then checking for correctness. It meant computationally tractable ways to find optimal solutions to all sorts of packing and scheduling problems. No industry would be unaffected. Grant and Duncan would be heroes for the ages.

“Show me.” Grant tried to sound bored.

The proof of ten as a solitary number transformed into pieces of muslin. They changed shape as they slid around Duncan’s body. A lemma around Duncan’s back fortified two results on his shoulders. What covered his chest seem to stay there out of sheer faith that someday something might hold it in place. He’d built it on conjectures Grant didn’t recognize. After a minute, Duncan wore something that fit roughly on him, pinned together by hope and determination more than it was stitched together by mathematical theorems and logic.

“Well?” Duncan showed his palms to Grant. Rather than casting his light on the world, Duncan looked as if he were in eclipse.

Grant let the outline inhabit his mind. Not enough hung on Duncan to prove anything. Grant wasn’t even sure what it actually proved, but the bits that were actually stitched together dazzled. The intermediate results, if verifiable, would advance mathematics nearly as much as the conclusion. What was missing defined the structure as much as what was there.

Grant’s hands gripped the chair. He forced himself not to engage with proof. Math hadn’t excited him this much in years. But was it worth being burned by the sun and shocked by lightning again? They had never been, and could never be, just about the math.

“By the age of thirty-five, most mathematicians have already done their best work.” Grant didn’t see any reason to be harsh, not when Duncan had been thoroughly, if bewilderingly, non-toxic. “You’ll want someone in his or her prime.”

The outline transformed back into the proof of ten as a solitary number. Its austere elegance replaced the buzz of the outline in Grant’s mind.

“Do you need to see your video again? This has nothing to do with age.” Duncan frowned. “Tsai, I can’t change how I treated you but—”

“I have grad students now.” Grant’s thighs burned as he stood. “I can’t just abandon my kids.”

Maybe that wasn’t the real reason either, but like his age, it was the truth. Grant pushed himself to the door.