`BookProof.ChapterE3.eulerJ_sq` (l w : Fin n → ℝ) (hll : ∑ i, l i * l i = 1) (hww : ∑ i, w i * w i = 1) (hlw : ∑ i, l i * w i = 0) : eulerJ l w * eulerJ l w =

Initializing...

`BookProof.ChapterE3.eulerJ_sq` (l w : Fin n → ℝ) (hll : ∑ i, l i * l i = 1) (hww : ∑ i, w i * w i = 1) (hlw : ∑ i, l i * w i = 0) : eulerJ l w * eulerJ l w = - (Matrix.vecMulVec l · Prove2Me