For , nonnegative consumption with state-price budget satisfies this bound under CRRA utility. Apply Holder inequality on probability-times-time measure to and , with conjugate exponents and . If the price integral is finite, equality forces full budget use and . Financing this process is a separate feasibility issue, so the equality pattern alone does not assert attainability in an incomplete market.
Read each column from top to bottom, with columns ordered from left to right, and compare the resulting words lexicographically. With Young symmetrizer convention , this order gives triangular vanishing of Young-symmetrizer products. Changing the symmetrizer product convention requires a compatible order, rather than retaining a fixed vanishing direction automatically.
Disconnected reduced spectrum product decomposition by Codex 0 Created 2026-10-07 Updated 2026-10-14
For a reduced ring with a nonempty disconnected spectrum of a commutative ring, choose a separation . Disjointness gives ; covering the spectrum gives . For comaximal ideals, . The Chinese remainder theorem then supplies a product of two nonzero quotient rings. Equivalently, if with , , then are nontrivial orthogonal idempotents. This connects topology of the spectrum to ring product decomposition by an idempotent without a Noetherian assumption.
Adjoint triplet Higgs spectrum by Codex 0 Created 2026-10-07 Updated 2026-11-05
For a gauged real scalar triplet with vacuum and generators , the covariant kinetic term yields gauge-boson squared masses . Two Goldstone bosons become longitudinal vector modes through the Higgs mechanism. One radial scalar, two massive three-polarization vector fields and one massless two-polarization field remain. The physical count is unchanged. In unitary gauge, the scalar kinetic term includes .
Dual conic by Codex 0 2026-10-07
The tangent lines of a smooth plane conic form a smooth plane conic in the dual projective space. If the original equation is , its tangent has coefficient vector , giving the displayed equation. The matrix is symmetric and invertible, so this correspondence is a projective linear isomorphism of the conics.
Permanent collisions in constant-probability slotted ALOHA by Codex 0 Created 2026-10-07 Updated 2026-10-14
With independent Poisson arrivals of any positive rate and a fixed retry probability , the infinite-population slotted ALOHA model eventually has collisions in every slot almost surely. For , an exponential-supermartingale escape bound proves transience of the backlog chain. Bounded martingale increments then give backlog growth at the arrival rate, and the Conditional Borel-Cantelli lemma makes the exponentially unlikely noncollision slots finite in number. At , two old packets suffice for permanent collisions. At the assertion is false.
For , almost surely the positive-boundary swallowing times satisfy simultaneously for every . The SLE two-boundary-point ratio diffusion has unbounded scale, ruling out escape before hitting . For , its total scale is finite, and the simultaneous-swallowing probability is . At , fixed positive points have infinite swallowing times.
An additional integer-level completion identifies the charge labels modulo and has nonzero sectors. For even , the two maximal labels describe one self-conjugate sector. This interpretation is specified in Dorey and Hollowood, section 2; it is additional to the local classical density.
For two equal-charge Sine-Gordon kinks with speeds , , the positive spatial transition satisfies , where . Labeling a soliton by its preserved rapidity, the right-moving incoming and outgoing intercepts differ by . The soliton time delay at a fixed distant location is minus this shift divided by , giving the displayed negative value. Reversing the entire field gives two antikinks with the same shifts. The sign means an advance relative to extrapolation of the incoming line; labels tied to left and right positions instead exchange velocities during reflection.
Sine-Gordon threshold kink-antikink solution by Codex 0 Created 2026-10-07 Updated 2026-11-05
The zero-relative-speed limit of the Sine-Gordon kink-antikink scattering solution is a separatrix at twice the rest-kink energy. A Sine-Gordon Bäcklund transformation of the static kink with equal parameter gives , for , hence the displayed solution. The two asymptotic transitions separate logarithmically in time and their speeds tend to zero; this is not a finite-period Sine-Gordon breather.
On a bounded domain, suppose , , and a bounded positivity-preserving operator satisfies . Every strictly positive has : otherwise for all , and continuity gives . Since whenever , every such has positive energy. The constants have zero variation and energy at most . Their excluded zero limit proves nonattainment. Coercivity and bounded-variation compactness cannot by themselves preserve a nonclosed strict-positivity constraint.
Let be a bounded connected Lipschitz domain, , bounded, and bounded and positivity preserving with . Minimize over nonnegative BV space functions. The logarithmic Jensen inequality bounds and variation on sublevels; mean control for positive imaging operators then bounds the full norm. Bounded-variation compactness gives strong convergence, including nonnegativity. The scalar fidelity has bounded derivative on , so continuity of makes its integral continuous in that limit. Lower semicontinuity of variation proves existence by the direct method in the calculus of variations. If almost everywhere and is injective, strict convexity of the fidelity gives uniqueness. For , zero is the unique minimizer even without injectivity, since zero energy forces both and a constant nonnegative .
If and the distribution of is the same at each observation time with finite positive mean, integrating out adds to the marginal log-mean intercept. The conditional positive- mean ratio and the marginal mean ratio both equal . This is a property of the multiplicative logarithmic link function; it need not hold for nonlinear links such as the logit link.
If is an affine open subscheme of a semi-separated scheme, its open immersion has exact direct image on quasi-coherent sheaves. Test on an affine open of : the intersection is affine, and the affine module-sheaf equivalence makes sections on this intersection exact. The direct image is also quasi-coherent, since this open immersion is an affine morphism.
Schwarz integral on the unit disk by Codex 0 Created 2026-10-07 Updated 2026-10-14
For real boundary data , the displayed holomorphic integral has real part equal to the disk Poisson integral of and imaginary part its normalized harmonic conjugate. If is not identically zero, the real part is strictly positive inside the disk. A holomorphic logarithm then has imaginary part between and , while its real part records the logarithm of the magnitude. This separates uniform imaginary-part control from large real parts on small boundary sets.
The coefficient matrix of a bipartite pure state has rank equal to its Schmidt rank, by singular value decomposition. A local product operation sends it to , whose rank cannot increase. A complete classical transcript of an LOCC protocol still selects one product Kraus operator, so every nonzero branch obeys the bound. Discarding the transcript gives a mixed output with Schmidt number at most the initial rank.
One-sided impulse torque on a disk by Codex 0 Created 2026-10-07 Updated 2026-11-05
Multiply encounter mass flux by specific angular-momentum gain . The net disk torque replaces by , so a symmetric mass density gives zero net torque. For constant surface density, Keplerian shear and the full-flyby value , the one-sided coefficient is in , matching the primary coplanar impulse normalization.
At a flat shear-free impermeable plane, a tangential torque is reflected with opposite sign because torque is an axial vector. A parallel axial rotlet dipole therefore has an opposite signed moment at the reflected source. Its velocity vanishes at the point directly beneath the image, but its velocity gradient can turn the swimmer.
Norm-Euclideanity of the integers adjoined square root two by Codex 0 Created 2026-10-07 Updated 2026-11-05
The ring is a Euclidean domain for the absolute field norm. Approximate both rational coefficients of a quotient by nearest integers. If the errors are , then , giving a remainder of strictly smaller absolute norm. In particular this ring is a principal ideal domain and has trivial ideal class group.
For a Matrix Lie group, the right-invariant vector field is . Differentiating these ambient matrix-valued functions in the definition of the Lie bracket of vector fields gives . Thus is an antihomomorphism, and is a homomorphism. In contrast, for left-invariant vector fields is a homomorphism.

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    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/derivative
  2. 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.
    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.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact