Annals of Mathematics, 150 (1999), 1177–1179 Addendum to Classification of irreducible holonomies of torsion-free affine connections By Sergei Merkulov and Lorenz Schwachhöfer* The real form Spin(6, H) ⊂ End(R32 ) of Spin(12, C) ⊂ End(C32 ) is absolutely irreducible and thus satisfies the algebraic identities (40) and (41). Therefore, it also occurs as an exotic holonomy and the associated supermanifold Mg admits a SUSY-invariant polynomial. This real form has been erraneously omitted in our paper. Also, the two real four-dimensional exotic holonomies, whose occurrences were unknown at the time of writing, have been shown to exist very recently by R. Bryant [B]. With these corrections, Table 3 and the table in Theorem C should read as follows. ∗ The original article appeared in 150 (1999), 77–149. 1178 ¨ SERGEI MERKULOV AND LORENZ SCHWACHHOFER Table 3: List of exotic holonomies group G representation V TR · Spin(5, 5) R16 R16 C16 ' R32 TR · Spin(1, 9) TC · Spin(10, C) R27 R27 TR · E16 TR · E46 TC · EC 6 C27 ' R54 TR · SL(2, R) ¯ 3 R2 ' R4 C∗ · SL(2, C) R∗ · Sp(2, R) C∗ · Sp(2, C) ¯ 3 C2 ' R8 SL(2, C) ¯ 3 C2 ' R8 C R∗ · SO(2) · SL(2, R) C∗ · SU(2) R4 4 ' R8 R2 ⊗ R 2 ' R4 C2 ' R4 C2 ' R4 C2 ' R4 Hλ · SU(2) Hλ · SU(1, 1) SL(2, R) · SO(p, q) R2 ⊗ Rp+q ' R2(p+q) Hn ' R4n C2 ⊗ Cn ' R4n Sp(1) · SO(n, H) SL(2, C) · SO(n, C) >3 n>2 n>3 p+q R56 R56 E57 E77 EC 7 R112 ' C56 Sp(3, R) R14 ⊂ Λ3 R6 R28 ' C14 ⊂ Λ3 C6 Sp(3, C) SL(6, R) R20 ' Λ3 R6 R20 R20 R40 ' Λ3 C6 SU(1, 5) SU(3, 3) SL(6, C) R32 R32 R32 C32 ' R64 Spin(2, 10) Spin(6, 6) Spin(6, H) Spin(12, C) Notation: restrictions/remarks TF denotes any connected Lie subgroup of Hλ = © e(2πi+λ)t | t ∈ R ª ⊆ C∗ , λ > 0. F∗ , ADDENDUM: CLASSIFICATION OF IRREDUCIBLE HOLONOMIES 1179 Table from Theorem C Group G Representation space Group G Representation space Sp(n, R) R C2n E57 R56 R56 C56 R32 R32 R32 C32 2n Sp(n, C) SL(2, R) R4 ' ¯ 3 R2 C4 ' ¯ 3 C2 SL(2, C) SL(2, R) · SO(p, q) SL(2, C) · SO(n, C) Sp(1)SO(n, H) SL(6, R) SU(1, 5) SU(3, 3) SL(6, C) E77 R 2(p+q) , p+q >3 C2n , n > 3 Hn ' R4n , n > 2 R20 ' Λ3 R6 R20 R20 C20 ' Λ3 C6 E7C Spin(2, 10) Spin(6, 6) Spin(6, H) Spin(12, C) Sp(3, R) Sp(3, C) R14 ⊂ Λ3 R6 C14 ⊂ Λ3 C6 Glasgow University, Glasgow, UK E-mail address: sm@maths.gla.ac.uk Mathematisches Institut, Universität Leipzig, Leipzig, Germany E-mail address: schwachh@mathematik.uni-leipzig.de References [B] R. Bryant, Recent advances in the theory of holonomy, Séminaire Bourbaki, 51ème année, 1998-99, n◦ 861; xxx mathematics e-print archive: math.DG/9910059; Astérisque, to appear.