Ball, W. W. Rouse (Walter William Rouse), 1850-1925 · London, Macmillan · leaf 78
, B, and G, itis not necessary to colour them all differently, and thus themost unfavourable case is that already treated. Moreover any * Leipzig Transactions {Math.-phys. Glasse), 1885, vol. xxxvii, pp. 1—6. t See Proceedings of the Royal Society of Edinburgh, July 19, 1880, vol. x,p. 728. X… … 66 GEOMETRICAL RECREATIONS [CH. Ill of the above areas may diminish to a point and finally disappearwithout affecting the argument. That we may require at least four colours is obvious fromthe above diagram, since in that case the areas A, B, G, and Xwould have to be coloured differently. A proof…
Mathematical recreations · Geometry · Astrology · Space and time · Matter · Magic squares
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