I'm trying to find the name of a science fiction omnibus that I read between 1985 - 1989. I remember two short stories in this omnibus, one was about aliens that visited Earth and a man was trying to trade paint for some of their technology.
Another was of a machine intelligence that time travelled to the past and met itself in its earlier form. I'd like either the name of either the omnibus in question or the names of these two short stories.
The second story sounds like the novelette "Fulfillment" by A. E. van Vogt:
The truth has already been verified by my integrating interoceptors. The Brain and I are one—but thousands of years apart. If the Brain is destroyed in the twentieth century, then I will not exist in the thirtieth. Or will I?
The other short story sounds familiar, but I can't place it.
The ISFDB page for "Fulfillment" lists all the anthologies and collections it has appeared in. Maybe you will recognize the one you're looking for by the cover or the contents.
First story is almost certainly Clifford Simak's "The Big Front Yard" -- the trading of ideas (with the protagonist offering paint) is a key identifier. A story summary at:
http://variety-sf.blogspot.com/2008/06/clifford-d-simak-big-front-yard.html
includes this and other details to demonstrate the match.
I also agree with the ID of the second story. I'm not sure there's a single collection that includes both.
