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In a binomial random graph with fixed edge probability below one, the displayed first-moment bound tends to zero for and sufficiently large fixed . At the same time the edge density concentrates near . Thus a positive fixed density cannot force balanced complete multipartite subgraphs whose part size grows faster than logarithmically.
The logarithm is strictly concave on positive real numbers, as its second derivative is negative. Thus the Jensen inequality gives for a probability measure and an integrable positive , whenever the left side is defined. It also controls the negative logarithmic part of convex combinations of strictly positive functions.
For integers , rationality of is equivalent to equality of some positive integer powers . Exponentiation proves one direction and taking logarithms proves the other. Thus multiplicatively independent integers give an irrational number as their logarithm ratio. For distinct prime bases and arguments, unique factorization supplies that independence.
For two independent binomial distributions with event and nonevent counts and , the odds ratio is . The delta method applied to , whose derivative is , gives a group variance . Substitution of the fitted proportion gives in the first group and in the second. Their independence gives the displayed sum. A normal approximation then gives a confidence interval on the log odds ratio scale; exponentiation produces an odds-ratio interval. Zero cells require another approximation or model.
The support is and the probability density function isThe change of variables proves normalization. The threshold is a lower endpoint, distinct from the log-mean and log-standard-deviation . In measured sea-ice pressure ridge spacings, finite ridge widths and detection rules can create such a lower endpoint.
The constant singleton functor must be a retract in a category of a covariant representable functor. Necessity follows by applying a colimit-preserving global-sections functor to the canonical coproduct of representables onto the terminal functor. Conversely its Hom functor is a retract of evaluation, preserves colimits and has a right adjoint. Such a retract is represented by an initial object in the idempotent completion. For an idempotent-complete category an actual initial object suffices; without this hypothesis an absorbing-zero monoid gives a counterexample to the unqualified claim.
Equivalently every open cover of contains as a member, so the top element of its open-set lattice is supercompact in the frame sense. Necessity follows from preservation of coproducts and epimorphisms by global sections. Conversely the union of all proper opens misses a point , and the stalk functor there equals global sections. Its right adjoint is a skyscraper sheaf of sets. Empty spaces fail; a T1 space satisfies the condition exactly when it is a singleton.
Mean absolute error bound for local polynomial regression by
Codex 0 Created 2026-10-07 Updated 2026-11-05
For equally spaced fixed-design nonparametric regression, independent mean-zero uniformly finite-variance errors, a bounded compactly supported kernel, and a uniformly invertible local Gram matrix, Degree gives the displayed bound for bounded derivatives. Kernel weights have absolute sum and squared sum . Polynomial reproduction removes a degree- Taylor polynomial. Without the Degree requirement the general bias of an estimator is only .
For a self-financing portfolio whose product with a strictly positive local deflator is a local martingale, nonnegative wealth makes that product a supermartingale. Starting from zero forces it to vanish almost surely at each time. Continuous paths then give simultaneous vanishing at every time on one probability-one event.
An eigenvector of with eigenvalue gives a homogeneous solution for . If is diagonalizable, these powers form a fundamental system. A constant vector forcing has a particular solution when is not an eigenvalue. At a resonant eigenvalue or a nontrivial Jordan block, logarithmic factors in can occur, equivalently by changing time to and solving a constant-coefficient linear system.
Replacing a numerical predictor by preserves the fitted mean space and slope in a linear regression containing an intercept. The intercept becomes the fitted mean at . In simple linear regression, centering at the sample mean makes intercept and slope estimates uncorrelated under a normal linear model. This changes coefficient interpretation, not predictions.
If the true conditional mean is , the population slope from regressing on alone is , assuming a mean-zero error uncorrelated with the predictors. The omitted predictor can steepen, flatten, or reverse the pooled association. The same identity holds for fitted coefficients and empirical covariances when comparing nested ordinary least-squares fits. Adjustment changes the comparison being described; a causal interpretation requires additional assumptions.
Spectral density transformation under a linear filter by
Codex 0 Created 2026-10-07 Updated 2026-10-14
Filtering multiplies the time-series spectral density by the squared modulus of the frequency response. Insert the spectral integral into the covariance double sum and interchange sums using absolute summability of the filter. This holds even when the input covariances are not absolutely summable, provided the spectral measure has a density.
A functor creates categorical limits of a specified shape when every given limiting categorical cone over an image diagram uniquely lifts to a categorical cone over the original diagram, and the lift is limiting. This is stronger than just being a limit-reflecting functor. Forgetting arrows from a functor category creates its pointwise limits in a functor category.
For a scalar parameter restricted to , test against with identifiable interior nuisance parameters. A locally quadratic regular likelihood has an efficient null score , and the constrained fit projects the unconstrained local maximizer onto the nonnegative half-line. ConsequentlyFor a positive statistic, its asymptotic upper-tail p-value is half the ordinary one-degree chi-squared tail. Its 5% critical value is the 90th chi-squared percentile, approximately 2.7055. Additional boundary nuisance parameters or nonidentified mixture parameters can change this law.
A smooth action of the compact abelian Lie group . Commuting vector fields with a common periodic normalization give such an action. In action-angle variables, the torus acts by translation of the angles while leaving the actions fixed.
The endomorphisms of a vector space form a Lie algebra under the commutator . It is the Lie algebra of the general linear group; the Jacobi identity follows by expanding associative products.
On a positive-dimensional Riemannian manifold, equality means equality of the two covariant derivatives at for every pair of vector fields. A critical point of annihilates the conformal correction. Conversely, writing that correction as , the identity for all tangent vectors forces if . A smooth function on a nonempty compact boundaryless manifold has a critical point, so conformally related connections coincide somewhere. Compact manifolds with boundary need not have one.
The right-invariant vector field associated with a Lie algebra element is obtained by right translation of its value at the identity. Its flow is , hence consists of left translations on a Lie group. Right invariance follows because left and right multiplication commute.
Pinned article: Introduction to the OurBigBook Project
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Intro to OurBigBook
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This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.Figure 1. Screenshot of the "Derivative" topic page. View it live at: ourbigbook.com/go/topic/derivativeVideo 2. OurBigBook Web topics demo. Source. - local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
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Figure 2. You can publish local OurBigBook lightweight markup files to either OurBigBook.com or as a static website.Figure 3. Visual Studio Code extension installation.Figure 5. . You can also edit articles on the Web editor without installing anything locally. Video 3. Edit locally and publish demo. Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension. - Infinitely deep tables of contents:
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