Arbital features

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A page is the primary building block in Arbital. Most pages fall within one of these categories:

All pages in the math domain are “wiki” type pages, meaning they are open to public for proposed edits.

Parents, children, and the page hierarchy

Arbital pages have many kinds of connections, parent-child relationship being the strongest one. Each page can have multiple children and multiple parents, though one parent is most common. The relationship implies that the child page is a critical component of the parent, or that the parent is the sum of its children. These relationships create a page hierarchy, which makes explaining, learning, and discovering easier.

Example: a Chemistry textbook will have its own Arbital page. Its children will be pages corresponding to different chapters. Their children will be pages corresponding to different sections. Their children will be pages corresponding to homework problems, experiments, or extra material. Each subpage is a critical component that makes the entire book work well.

Example: Addition, subtraction, multiplication and division pages are all children of arithmetic. We can say that arithmetic is “addition, subtraction, multiplication, and division.”


Aside from the parent-child relationship, pages can also have tags. These are similar to standard #hashtags, but each tag actually points to an Arbital page. Tags create more loose connections, implying that the page is talking about the tag, perhaps indirectly.

Example: A review of the Chemistry book wouldn’t be a child of the Chemistry book page. Instead, it would be tagged with the Chemistry book page.


To simplify each page the author(s) will assume that the reader already understands certain topics. These assumptions will be listed in the requisite section. While you can ignore them and continue reading, if the material is difficult or unclear, it’s likely because you don’t understand one of the concepts a page relies on. However, if you’ve met all the requirements, you can ask a question or suggest a requirement.

For this reason, every page has a section at the bottom where you can mark that you understand that page. Arbital will remember it and account for it when checking if you meet the requirements on other pages.

Example: a page on integrals will have the page on derivatives as one requirement among others.


Lenses are alternate tabs on a page which explain the same concept, but from different perspectives or with a different set of requisites. If you don’t meet requirements for the primary page, but still need to get a quick understanding, you can check out a lens, which will usually be written in a more accessible manner.

Example: the primary page on Derivatives will be talking about the concept using “limits” and complex math notations, whereas a lens can describe the same concept using the “tangent” concept and employing lots of pictures.

You can hover over any link that goes to an Arbital page to see the summary of that page, along with other information. This by itself might answer some questions you have, and will very likely help you see if that page is what you are looking for. If the page has any lenses, they will appear in the popover as well, so you can choose the summary that works for you.


Most pages have comments, where the readers discuss the contents of the page and related topics. The comments are organized in two tiers: top-level comments and replies to them. For this reason, if you have multiple points to make, please make each of them a separate comment. This way all the replies to each comment will be on that topic.

When you hover over a paragraph, you have the option of creating an inline comment, which will be attached to the selected text. This makes it more clear for other readers what you are referring to, and gives them the context to understand your comment or question.

Sometimes a page will have the comments disabled or restricted to make sure the quality of the conversation is high.

Questions and answers

If something is not clear to you, you can ask a question. This will create a new page, where you can also see all the answers. The functionality is very similar to StackExchange-type websites.

When you type up a question, you will see a list of other similar questions that have been asked. Please take a look to see if your question has already been asked and answered. Once you submit the question, users who are subscribed to the page will be notified, and one of them is likely to respond.


You can like any page or comment. Liking will help the page’s visibility, it will show up higher in search results, and the author(s) of the page will get karma.

Please note that liking a page is not at all the same as agreeing with the page. (See the Votes section for that.) Liking means you find the page valuable, and you think it does its job well: a page about a specific concept presents it clearly and concisely; a page about some area provides a comprehensive coverage, while highlighting important details; a lens presents the same concept from a different angle, while retaining accuracy and being up to date; a question is well written and on topic; an answer is helpful and answers the question; a comment is on topic, thought out, and provides insight.

Example: two sentence page on The Matrix film shouldn’t receive a like, since there isn’t enough content. Definitely do not like the page because you like the movie.

Example: three screen long post arguing that global warming is not caused by humans, citing various studies and positing an alternative, testable hypothesis deserves a like, even though you probably disagree with the conclusion. (See the Votes section below.)



There are several different types of votes:

  • Probability vote is for estimating the likelihood of some proposition.

  • Approval vote is for measuring agreement and disagreement with some proposition.

For all types of votes, you can see how other people have voted, and hover over any cluster of votes to see the corresponding user names.

Example: A page titled “Vitamin D helps prevent cancer” will have a probability bar.

Example: A page titled “Countries with unstable currencies should switch to Bitcoin” will have an approval bar. <div>


You can subscribe to pages to receive updates when interesting events happen: page is edited, a new comment is posted, a child is added, etc… You can also subscribe to users to get updates when they create a page or post a comment.


A group is a collection of users. You can see which groups you belong to on your Groups page. Being a member of the group will allow you to see the group’s private pages (see “Private domain” section below) and edit most pages that the group owns. You might have additional admin abilities like adding/​removing group members.


Private domain

Each group has a corresponding private subdomain at All the pages in that subdomain are private to the group, and can’t be seen by anyone else. When you create a page in that subdomain, it will be private by default. Any page on the default are public and can be seen by anyone. <div>