Bourbaki

Corollary

Tag 00LD, permanent. Cite it as [Bourbaki, Tag 00LD].

Algebra, VIII, p. 356, § 18. Simple Algebras over a Finite Field

Let VV be a vector space of finite dimension nn over KK and II a finite set, and for each i∈Ii \in I, let Fi:V→KF_i : V \to K be a homogeneous polynomial mapping of degree di>0d_i > 0. If we have ∑i∈Idi<n\sum_{i \in I} d_i < n, then there exists a nonzero element xx of VV such that Fi(x)=0F_i(x) = 0 for every i∈Ii \in I.

Let (e1,…,en)(e_1, \ldots, e_n) be a basis of VV over KK. By the definition of homogeneous polynomial mappings (IV, §5, No. 9, p. 55, Definition 3), for every i∈Ii \in I, there exists a homogeneous polynomial fif_i in K[X1,…,Xn]K[X_1, \ldots, X_n] of degree did_i such that we have Fi(ξ1e1,…,ξnen)=fi(ξ1,…,ξn)F_i(\xi_1 e_1, \ldots, \xi_n e_n) = f_i(\xi_1, \ldots, \xi_n). Let ZZ be the set of elements xx of VV such that Fi(x)=0F_i(x) = 0 for every i∈Ii \in I. By Theorem 1, the cardinal of ZZ is divisible by pp, and since 00 belongs to SS, we have Card⁡(Z)≥p>1\operatorname{Card}(Z) \geq p > 1.

Bourbaki sets the proof directly after the statement, and the corpus does not separate them, so what is above is the statement and its proof together.

Cited by

Nothing.

Cites

  • IV, §5, No. 9, p. 55, Definition 3 not in this corpus
  • Theorem 1
Transcribed from the printed edition, 2023, Springer Nature. Not translated.