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Diaspora by Greg Egan
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Diaspora (1997)

by Greg Egan

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Let’s try an experiment.

Make a rectangle of paper with y width and y times 3.14 length with a little excess enough to connect the ends. Twist the rectangle and connect the ends into a Möbius strip. You'll wind up with something that looks like two joined cones and almost a solid. I like to call it a "Möbius mollusk" since it resembles a conical seashell. Like a seashell it has an opening, two in fact, that I call "ears". Now you can make smaller Möbius mollusks of the original width divided by 1.61 (Phi) with a length again of that new width times 3.14. These smaller Möbius strips will nest recursively into the ear of each previous larger strip.

However, it seems if you try to pack the second ear with recursive strips they will not stay, but are forced out by the tension in the paper. Finally, I am strictly amateur hour in terms of mathematics, but I believe the use of Pi makes it a limiting factor, in that trying to use a wider strip of paper will produce a kink in an otherwise smooth curve.

Regarding the “nesting of the Möbius bands”, it is easier to imagine a Möbius band made of red paper. Apply blue paint on the strip. The blue paint will completely envelop the red all the way on both sides. Then, if you cut the paper, you will see the red color sandwiched between blue colour. This means that the blue-colored Möbius strip is not a strip but actually a tube, i.e. a torus. Therefore, as the article declares, this is not a good method for embedding an uncountably infinite number of Möbius bands.

Considering an “Alexander horned sphere” of just two interlocking tori, this can be unraveled to a double torus as shown in Problem 1.1 of Ivan Prasolov’s “Intutive Topology” displayed here https://sites.oxy.edu/rnaim... .

Then, if I consider an “Alexander horned sphere” of only four interlocking tori, this can be unravelled into a quadruple torus, a “four-petalled flower”. Keep the “complex-parts” - i.e. the small interlocking earrings - “rigid” and unravel the wider interlocking tori by the method above. In the end, each complex-part may be positioned on opposite sides of the resulting double torus. Then proceed to unravel the tori of the complex-parts.

Using the same method recursively, I would intuitively expect for the Alexander horned sphere to unravel into an infinite-petalled flower.

Is this infinite-petalled flower a “wild” embedding?

I don't have access to the paper but this seems like normal geometric topology to me. I would think that if there's anything going on in 'point-set topology' research it'd be closer to set theory and logic than this.

This novel reminds me of physicists (like Feynman) who describe quantum mechanics as already having an infinite existence, but when say, you have a 50/50 chance observation, that just means 50% of the infinite existence goes one way while the other 50% goes another (same as MWI except it's not that the universe splits upon measurement, instead it was always infinite and given percentages develop down different paths). It's just a matter of the pop-level narrative, because of course that's always what MWI was saying; Everett's vision of the multiverse as a grand cathedral of infinite, timeless existence obeying the Schrodinger equation as if it were singing a hymn to God's perfection. Thus rescuing the orderly world of Newton and Leibniz from the terrifying combat of unpredictable quantum events, from randomness that is either the spark of life or discord in the harmony of the universe, depending on your personality.

Bottom-line: Once again, Egan “conjures” whole societies (e.g., the Bridgers, the Gleisners) as characters, and develops that. The books are, in part, about the new modes of being that could arise from technology and how these different groups would interact. Nobody can accuse him of not having enough new ideas. If anything, his books always feel as if he'd run out of time and tried to rush a ton of ideas into the last few chapters (especially in “Schild's Ladder”). “Diaspora” made me realize that all the SF that I had come across before were crudely anthropomorphic and infantile, in plot and message. This probably sounds like hyperbole, but I come from growing up on some very infantile SF...”Diaspora” goes beyond having a high reading level; it has high knowledge requirements, ones which most authors would struggle to comprehend. This lets Greg Egan write plots that are more profound than a typical novel could be. I loved it cover to cover as well, and I wouldn't want to read SF written any other way!

SF = Speculative Fiction. ( )
  antao | May 2, 2019 |
This novel is BIG. You may think you've read sci-fi tales played out on vast scales, but compared to “Diaspora,” all those “epic” stories are little more than the churning of anthills.

All the traditional sci-fi concepts are here, but they've been expanded so adroitly, so meticulously, that it all feels fresh. The discussions on identity and mental states were so incredible I could feel my own mind changing, in strange mimicry of the characters and their “outlooks.”

The quest of Yatima and his companions goes so far beyond the expected space-time continuum that it's hard to fathom. The end of the novel will leave you gobsmacked. Have they really gone this far? How much further will Yatima go still? Is Yatima's fate a blessing or a curse...or will it flip-flop between the two as the eons pass?

The xenobiology, the celestial calamities, the massive engineering projects, the elusive Transmuters, always just out of reach...it's all exquisitely detailed.

But that detail is a double-edged sword. Reading “Diaspora” is like reading a textbook. All of its concepts are discussed seriously and at great length. There are few summaries or shortcuts. I probably didn't understand half the novel.

If Egan had pulled back just a little, if he'd helped us along instead of dumping esoteric data on us and expecting us to slog through it on our own, this novel would be nearly perfect. As it's written, though, it's nearly undecipherable to the layperson.

Its concepts are still so dazzling that they'll stick with me for a long time, but to absorb the barest understanding of them required a ton of work. Those with scientific expertise may be in heaven if they try this novel, but I can't recommend it to the casual reader. ( )
  roguehomebody | Nov 13, 2018 |
While I liked *Greg Egan*'s other novels, **Diaspora** didn't grip me at all and was very hard to get through. The fact that it revolves around an advanced species that can change itself to any degree it wants to made it hard to feel sypathy with any of the characters. The beginning was really strong, describing how their civilizations and personalities are formed. But after that, to my feeling the book consisted only of excalating physicsbabble and arbitrary personality changes, and this escalation continued right upon the not quite satisfying end. ( )
  _rixx_ | Aug 30, 2018 |
"Diaspora" by Greg Egan (1997) is of mixed quality. The novel was written to fit around a short story that Egan published earlier, "Wang's Carpets." That short story appears as Chapter 11.

From the start of the book through the end of Chapter 6 (Parts 1 and 2), Diaspora offers some of the best science fiction I've read. It is chock full of fascinating ideas, the plot is engaging and exciting, and you care deeply about the characters.

Chapter 11, "Wang's Carpets," is another bright, high point in the novel.

Unfortunately, these high-quality sections only make up about a third of the novel. The remaining chapters are of much lower quality, and that quality gradually diminishes further as the end of the novel approaches. The important characters become less and less relateable, and Egan spends too much time philosophizing over fictional mathematics and physics. The last third of the book is a wild goose chase, whose ultimate conclusion is deeply unsatisfying and more than faintly ridiculous. I was left feeling cheated, as though Egan demonstrated his tremendous ideas and ability, then strung me along, promising more and failing to deliver.

It is difficult to assign a star rating to a book with both excellent and disappointing segments. I ultimately decided to award four stars, which I consider a generous rating for a book that was one-third excellent, one-third mediocre, and one-third poor.

If you wish to experience the good parts of Diaspora, you are in luck: Parts 1 and 2 (chapters 1 through 6) stand on their own as a self-contained story. You can read these chapters and then stop. Or, if you prefer, you can read from chapter 1 through chapter 11, which will cover all of the book's high points while avoiding the worst parts, which come near the end. If you proceed all the way through, you will find that nuggets of value become increasingly scarce, lost in a seemingly five-dimensional scape of bland text.

If you are interested in Diaspora, consider "Blindsight" by Peter Watts, a story that has a similar style but is strong from beginning to end. ( )
  jrissman | Aug 1, 2018 |
hard sci-fi at its finest ( )
  bookwormelf | Mar 22, 2018 |
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Author nameRoleType of authorWork?Status
Egan, Gregprimary authorall editionsconfirmed
Brambilla, FrancoCover artistsecondary authorsome editionsconfirmed
Gudynas, PeterCover artistsecondary authorsome editionsconfirmed
Martinière, StephanCover artistsecondary authorsome editionsconfirmed
Valla, RiccardoTranslatorsecondary authorsome editionsconfirmed
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Yatima surveyed the Doppler-shifted stars around the polis, following the frozen, concentric waves of colour across the sky from expansion to convergence.
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Amazon.com Amazon.com Review (ISBN 0061057983, Mass Market Paperback)

In the 30th century, few humans remain on Earth. Most have downloaded themselves into robot bodies or solar-system-spanning virtual realities, escaping death--or so they believe, until the collision of nearby neutron stars threatens life in every form.

Diaspora, written by Hugo Award and John W. Campbell Memorial Award winner Greg Egan, transcends millennia and universes in the tradition of Poul Anderson's Tau Zero, Bruce Sterling's Schismatrix Plus, Camille Flammarion's Omega, and Olaf Stapledon's Last and First Men. Diaspora is packed with mind-bending ideas extrapolated from cutting-edge cosmology, physics, and consciousness theory to create an astonishing hard-SF novel inhabited by very strange yet always believable characters. Diaspora is why people read SF. --Cynthia Ward

(retrieved from Amazon Thu, 12 Mar 2015 18:25:39 -0400)

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In the 30th century, Earth is dying and the world's three separate intelligences unite to search for a new home. One intelligence is the regular flesh and blood, another is android and the third is bodiless software. The hero is Yatima, an android who leads an exploration party, and on the voyage he meets new civilizations.… (more)

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