Revision history of "Hairy ball theorem"

This is a list of past revisions of Hairy ball theorem. Each is preserved exactly as it was last seen, which is to say approximately, and not necessarily here. Diffs are unavailable; the two versions could not be brought to the same location at the same time.

External tools: Find addition/removal · Find which edit moved the page (inconclusive)

• cur | prev 2026 an editor (talk | contribs) . . (2,160 bytes) (+140) m . . (→ The interesting half: the odd spheres comb flat and the article had not been saying so. that is the fact worth having and the ball is the illustration) (current)
• cur | prev 22:06, 9 Feb 2021 a topologist (talk | contribs) . . (2,020 bytes) (+85) m . . (→ the theorem is about continuous fields. the hairs on an actual ball are finite in number with gaps between them, so nothing you have done to one bears on it either way)
• cur | prev 21:40, 9 Feb 2021 MudGeometer_1844_real (talk | contribs) . . (1,935 bytes) (+55) . . (I COMBED A BALL. IT WER FINE. THERE WER NO BALD SPOT ON IT AND I AM LOOKING AT IT NOW)
• cur | prev 2003 an editor (talk | contribs) . . (1,880 bytes) (+240) . . (→ it can be done: the paper constructing such antennas shows the theorem was answering a narrower question than the engineers put to it. an isotropic pattern is available if the polarisation is let vary from one direction to another, and what is forbidden is a fixed one)
• cur | prev 1990s a meteorologist (talk | contribs) . . (1,640 bytes) (−70) m . . (→ wind is not tangent. it goes up and down as well, a little. the horizontal part is tangent and that is what the theorem is about, and the difference matters more to us than to you)
• cur | prev 1960s a populariser (talk | contribs) . . (1,710 bytes) (+180) . . (→ added the cyclone: wind is a field on the earth, so somewhere there is none of it. this is the version everybody will remember)
• cur | prev 1950s an antenna engineer (talk | contribs) . . (1,530 bytes) (+260) . . (→ we have never managed one that radiates alike in every direction, and the theorem appears to say why: the far field lies flat against the sphere of directions and cannot have the one length all over it)
• cur | prev 1927 L. E. J. Brouwer (talk | contribs) . . (1,270 bytes) (−160) . . (→ rv. the fixed point theorem is not correct. a proof that a thing exists without producing the thing has produced nothing, and I am the man who wrote it)
• cur | prev 1926 H. Hopf (talk | contribs) . . (1,430 bytes) (+380) . . (→ the zeros carry indices and the indices add up to the euler characteristic. that is the whole of why it is the even ones: two against nothing)
• cur | prev 1912 L. E. J. Brouwer (talk | contribs) . . (1,050 bytes) (+400) . . (→ and for every sphere of even dimension. I have used the excluded middle to get it and I am aware that I have, and I am setting the objection down for the present)
• cur | prev 1901 N. Tesla (talk | contribs) . . (650 bytes) (+170) . . (→ I mean to transmit in every direction at once and without wires. I am told this page concerns the combing of spheres and I do not see what it has to do with me)
• cur | prev 1885 H. Poincaré (talk | contribs) . . (480 bytes) (+480) . . (created page; a continuous field of tangents on the sphere must fail somewhere. I have it for the surface one can look at and I say nothing about the rest)

Older revisions exist but have not been located. The page is believed to retain a full history; it is simply not all in one place.