Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.


Conjuring with conjectures

The Clay Mathematics Institute is offering a million dollars for a solution to the Poincaré conjecture, and Grisha Perelman may have found one. What is the conjecture, and why does it matter?

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Figure 1: Testing topology.



  2. Perelman, G. Preprint math.DG/0211159 at <> (2002).

  3. Perelman, G. Preprint math.DG/0303109 at <> (2003).

  4. Stewart, I. Flatterland (Macmillan, London, 2001).

    MATH  Google Scholar 

  5. Hamilton, R. S. J. Diff. Geom. 17, 255–306 (1982).

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Ian Stewart.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Stewart, I. Conjuring with conjectures. Nature 423, 125–127 (2003).

Download citation

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing