Doomsday conjecture

From Wikipedia, the free encyclopedia

In algebraic topology, the doomsday conjecture was a conjecture about Ext groups over the Steenrod algebra made by Joel Cohen, named by Michael Barratt, published by Lua error in package.lua at line 80: module 'Module:Footnotes/anchor_id_list' not found. and disproved by Lua error in package.lua at line 80: module 'Module:Footnotes/anchor_id_list' not found.. Lua error in package.lua at line 80: module 'Module:Footnotes/anchor_id_list' not found. stated a modified version called the new doomsday conjecture.

The original doomsday conjecture was that for any prime p and positive integer s there are only a finite number of permanent cycles in

ExtAs,(Z/pZ,Z/pZ).

Lua error in package.lua at line 80: module 'Module:Footnotes/anchor_id_list' not found. found an infinite number of permanent cycles for p = s = 2, disproving the conjecture. Minami's new doomsday conjecture is a weaker form stating (in the case p = 2) that there are no nontrivial permanent cycles in the image of (Sq0)n for n sufficiently large depending on s.

References