Free Aurora in Four Voices by Catherine Asaro, Steven H Silver, Joe Bergeron

1. The Dreamers of Nightingale
    He missed the sun.
    The planet Ansatz boasts one city, Nightingale, a gem that graces eternal night. Just as a diamond sparkles because light that ventures into its heart is captured, bouncing from face to face, so Jato Stormson was trapped in Nightingale. Unlike the light inside a faceted diamond, however, he could never escape.
    After a few years, his memories of home faded. He could no longer picture the sun-parched farm on the planet Sandstorm where he had spent his boyhood. It was always dark in Nightingale.
    The Dreamers — the artistic geniuses who created Nightingale — were also mathematical prodigies. That was why they named their planet Ansatz. It referred to a method of solving differential equations. Guess an answer, an ansatz, and see if it solved the equation. If it didn't, make another guess. Another ansatz. Jato felt as if he were trapped on a guess of a world.
    One night he went to the EigenDome, an establishment for dancing. He sat at a table and waited for the drink server, but the server never came to his table. That was why he rarely visited the Dome. The artist who had designed the place considered it aesthetic to have humans serve the drinks and the humans in Nightingale ignored him. But that night he was lonelier than usual and even the icy Dreamers were better than no company at all.
    Made from synthetic diamond, the Dome resembled a truncated soccer ball. Jato had looked up its history in the city library and found a treatise on how the Dome's shape mimicked the molecule buckyball. Its holographic lighting evoked the quantum eigenfunctions that described a buckyball. He didn't understand the physics, but he appreciated the beauty it produced.
    Tonight Dreamers were everywhere, dancing, talking, humming. Centuries of playing with their genes and living in perpetual night had bleached their skin almost to translucence. Their hair floated around their bodies like silver smoke. Light from lamps outside the Dome refracted through the diamond walls, gracing the interior with rainbows that collected on the Dreamers in pools of color. They glistened like quantum ghosts.
    Across the Dome, the doors opened. A spacer stood in the doorway, her body haloed by the rainbow luminance. This was no Dreamer. She looked solid. Sun-touched. She must have come in on one of the rare ships that visited Nightingale; rare, because the Dreamers allowed no immigration and most sun-dwellers found a city of unrelieved night depressing anyway. The only reason people usually came to Ansatz was to trade for a Dream.
    Ah, yes. The Trade.
    Dreamers make a simple offer; give one a pleasant dream and in return the Dreamer will give you a work of art. They allow you ten days to try. After that, you must leave Nightingale, trade or no trade. Considering the prices Dreamer art claims throughout the Imperialate, that trade seems astoundingly one-sided, the offer of great treasure for no more than a nice dream.
    Jato had let the lure of that promise fool him. He spent years saving for the ticket to Ansatz. But how do you give a dream? It was harder than it sounded, particularly given how sun-dwelling humans revolted the Dreamers. The same husky build and rugged looks that had won him such admiration back home repelled the Dreamers. Considering their disdain for ugliness, he feared they wouldn't even let him stay the ten days.
    They never let him go.
    So now he sat by himself and watched the spacer walk to a table across in the Dome. She wore dark pants tucked into boots and a white sweater with gold rings decorating the upper arms. Her clothing looked familiar, but Jato couldn't place why. She had no jacket; Nightingale's weather machines aided the planet's natural convection to keep the climate pleasant, free from the fierce winds the tore at the rest of Ansatz. Her hair was a cloud of black curls with gold tips, and dark lashes framed her eyes — green eyes, the color of a leaf in the forest. Her skin had