Geodesic
Even Whitehead Squares are Not Projective
Canadian journal of mathematics, Tome 29 (1977) no. 5, pp. 957-962

Voir la notice de l'article provenant de la source Cambridge University Press

The projectivity of the Whitehead square wn = [in, in ] in π2n-1(SN ) has been studied by Randall [6] who proved that if wn is projective then n must be a power of 2 or one less than a power of 2. Here we solve the question in the even case, proving by means of bo homology:Theorem. if and only if n = 1, 2, 4. 
Milgram, R. James; Zvengrowski, Peter. Even Whitehead Squares are Not Projective. Canadian journal of mathematics, Tome 29 (1977) no. 5, pp. 957-962. doi: 10.4153/CJM-1977-096-9
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