A note on Samelson products and mod p cohomology of classifying spaces of the exceptional Lie groups

Abstract

Let G be an exceptional Lie group G 2 , F 4 , E 6 , E 7 or E 8 , and also set p is the corresponding prime 7, 13, 13, 19 or 31 respectively. If we localize spaces at p, G can be decomposed into a product of spheres. Using this decomposition, we take some elements in the homotopy groups of p-localized G, and we offer some non-zero 3-fold Samelson products of them. This implies that the nilpotency class of the localized self-homotopy group of G is greater than or equal to 3. The key lemma for these results is about a calculation on the cohomology operator P 1 in the mod p cohomology of BG, where G and p are as above. During this calculation, we use some original ideas, which are also used in Kishimoto and Kaji (in press) [7] recently.