English
The Chebyshev polynomials T satisfy T_R(0) = 1 and T_R(1) = X, with T given by a recursion T(n+2) = 2 X T(n+1) − T(n).
Русский
Чебышёвские многочлены T удовлетворяют T(0)=1, T(1)=X и рекуррентному тождеству T(n+2)=2 X T(n+1)−T(n).
LaTeX
$$$T_R(0)=1,\\quad T_R(1)=X,\\quad T_R(n+2)=2X\\,T_R(n+1)-T_R(n)$$$
Lean4
/-- The canonical isomorphism between a module and the result of tensoring it
from the left by two mutually dual invertible modules. -/
noncomputable abbrev leftCancelEquiv : M ⊗[R] (N ⊗[R] P) ≃ₗ[R] P :=
(TensorProduct.assoc R M N P).symm ≪≫ₗ e.rTensor P ≪≫ₗ TensorProduct.lid R P