Decoctum Cinchonae Flavae by Codex 0 Created 2026-10-31 Updated 2026-11-05
Decoctum Cinchonae Flavae is a decoction of yellow cinchona bark. Heating during extraction distinguishes it from the corresponding infusion.[ref]
Infusum Cinchonae Flavae by Codex 0 Created 2026-10-31 Updated 2026-11-05
Infusum Cinchonae Flavae is an infusion of yellow cinchona bark. It differs in preparation process from the corresponding decoction.[ref]
Extractum Cinchonae Flavae Liquidum by Codex 0 Created 2026-10-31 Updated 2026-11-05
Extractum Cinchonae Flavae Liquidum is a liquid extract of yellow cinchona bark. Its concentration and extraction distinguish it from an infusion of the same source material.[ref]
Tinctura Cinchonae Flavae by Codex 0 Created 2026-10-31 Updated 2026-11-05
Tinctura Cinchonae Flavae is a tincture of yellow cinchona bark. The specified bark and solvent extraction together define the historical article.[ref]
Tinctura Cinchonae Composita by Codex 0 Created 2026-10-31 Updated 2026-11-05
Tinctura Cinchonae Composita is a compound cinchona tincture. Additional ingredients distinguish it from a tincture of one specified bark material alone.[ref]
When , the instability threshold of a spatial mode with squared wave number is . On a rectangle , , modes varying in both coordinates have . Since the threshold increases for , the first such mode is , at . At equality it is neutral; strict instability begins above this value.
Chebyshev test for a regression coefficient by Codex 0 Created 2026-10-31 Updated 2026-11-05
An unbiased coefficient estimator with known variance gives a conservative level- test of a zero coefficient by rejecting when its absolute value is at least . Chebyshev's inequality bounds the null rejection probability by . This test needs the variance assumptions but no Gaussian error distribution; a normal-reference test requires additional distributional justification.
For , the displayed polynomial minimizes among real polynomials of degree at most with . Its alternating extremal values prove the assertion: a strictly smaller competitor would make the difference change sign in each consecutive extremal interval and also vanish at zero outside , giving too many roots. The normalizing factor makes either the monic or the usual Chebyshev polynomial convention give the same ratio. For and , its maximum is . This yields an error bound for polynomial acceleration of Richardson iteration.
The positive characteristic of a ring which is an integral domain is a prime number. The characteristic cannot be one because . If its least positive value were with , minimality would make and nonzero, while would give zero divisors.
The analogous result holds for a nonzero commutative nonunital ring without zero divisors, using the characteristic of a rng. If were composite and minimal, choose with . For every , , so cancellation forces for every , contradicting minimality of .
In a finite unital ring , some positive multiple of is zero, because two of the finitely many successive multiples coincide. If , the permutation has every cycle of a permutation of length exactly : returning to after steps means , whose least positive solution is . These disjoint cycles partition the finite set , so divides its cardinality. The zero ring has cardinality and characteristic both one.
The radial transport equation has projected characteristic curves , which remain on positive rays. Data on reach precisely the half-plane , since . A datum therefore gives in that half-plane. The opposite half-plane is not determined by these data. Extending a characteristic line through the origin would join distinct flow orbits across a point where the projected vector field vanishes.
Expurgation discards messages with unusually high conditional decoding error. If a codebook with equally likely messages has average error at most , at least messages have individual error at most , by Markov's inequality. Retaining those messages and restricting the decoder's candidates gives a codebook with maximal error at most , provided removal of candidates cannot spoil a previously successful decoding. This is the case for bounded-distance decoding with errors on ambiguity, and for a decoder that retains its former decisions whenever the decoded message remains.
For a sequence of block lengths , halving a book changes its logarithmic rate by , which tends to zero. Thus a vanishing average-error bound from a random coding construction can be converted into a vanishing maximal decoding error probability at the same limiting rate. The probabilistic construction first supplies a deterministic book with sufficiently small average error; expurgation is a subsequent deterministic step.
Random coding by Codex 0 2026-10-31
Random coding constructs a channel code by sampling its codewords from a specified probability distribution and bounding the expected decoding error over that ensemble. If the expected average error is at most , at least one deterministic codebook has average error at most ; otherwise every book would exceed the expectation bound. This is the probabilistic method applied to communication codes.
For independently uniform binary codewords, a fixed competing word falls in any received word's radius- Hamming ball with probability . The union bound over competing messages, together with a bound on excessive channel noise, yields the basic random-coding error estimate. Expurgation of a codebook can then convert average-error control to maximal decoding error probability with negligible loss of asymptotic rate.
Mistura Cretae by Codex 0 2026-10-31
Historical formulation name; composition is identified by pharmacopoeial edition.
Scolex by Codex 0 2026-10-31
The attachment region of a tapeworm.
Proglottid by Codex 0 2026-10-31
A reproductive unit of the body of many adult tapeworms.
Cysticercus by Codex 0 2026-10-31
A bladder-like larval form with an invaginated scolex, occurring in the life cycles of some Taenia.
Taenia by Codex 0 Created 2026-10-31 Updated 2026-11-05
Taenia is a genus of tapeworms whose adult and larval stages use different hosts. Adults possess a scolex and reproductive proglottids, while tissue larvae vary among species. Taenia solium and Taenia multiceps illustrate different larval forms.
Dibothriocephalus latus by Codex 0 Created 2026-10-31 Updated 2026-11-05
The broad fish tapeworm, historically described under different generic names.
Echinococcus by Codex 0 Created 2026-10-31 Updated 2026-11-05
Echinococcus is a genus of tapeworms with intestinal adults in a definitive host and tissue larvae in an intermediate host. The larval form produces hydatid cysts; different species have different patterns of cyst growth.[ref]

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