Neumann Cosine Lean 4 library · release v0.1.0
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Modules

The library root imports every module below.

Module Contents
NeumannCosine.Basic The mode, its frequency, orthogonality and Gram values
NeumannCosine.Series.TermwiseIntegral Termwise integration of $\ell^1$ cosine series
NeumannCosine.Series.Products Products of $\ell^1$ cosine series, interchange with the integral, signed-index reindexing
NeumannCosine.KernelIntegrals Closed forms of integrals of products of three and four modes
NeumannCosine.ProductIdentities Integrals of products of two to four cosine series as constrained convolutions
NeumannCosine.Coefficients The class NeumannW21: $O(k^{-2})$ coefficients, summability, pointwise expansion
NeumannCosine.Sobolev.WeakDerivative Weak derivatives on $(0,L)$, du Bois-Reymond, absolutely continuous representative
NeumannCosine.Sobolev.H2Neumann $H^2(0,L)$ with Neumann trace lies in NeumannW21
NeumannCosine.DivergenceFormProjection $\lvert\int_0^L(R_0+R_1')\cos(k\pi x/L)\,dx\rvert\le(L+k\pi)B$ when $\lvert R_0\rvert,\lvert R_1\rvert\le B$ on $[0,L]$, $R_0$ is integrable, $R_1$ is absolutely continuous on $[0,L]$ (or continuous on $[0,L]$ and differentiable at every point of $(0,L)$ with integrable derivative), and $R_1(0)=R_1(L)=0$
NeumannCosine.Discrete.Eigenvalues Discrete and continuum eigenvalues, $\operatorname{sinc}^2$ relation, convergence, lower bound
NeumannCosine.Discrete.Laplacian The reflected three-point stencil on Fin (N + 1), its cosine eigenvectors and basis
NeumannCosine.Discrete.ModalMinimumTail One tail cutoff for all fine meshes, for a linearly coercive $f$
NeumannCosine.Discrete.ModalMinimumLimit The discrete modal minimum converges to the continuum infimum