If you have a Manifold Text (one that’s been converted and web-readable) hosted on OpenALG, we’ve had a way for the public to leave annotations for each other while engaging with these open resources. The advent of more sophisticated advertisement bots has allowed for a bad-faith practice to take place within Manifold Texts: the public annotations feature has been exploited to proliferate spam ads as annotations on resources.

Therefore, to protect the integrity of the resources we host, we are disabling public reading groups and public annotations on OpenALG—for now. If Manifold comes up with a way to combat spam and still encourage public annotations, we’ll open this feature back up. In the meantime, instructors should use only private reading groups, which require you to invite your students to the group. If you have been using a public reading group, please check up on the Private Reading Groups instructions here: Manifold: Reading Groups.

Lecture 19-1: Electric Potential Energy, Electric Potential, and Equipoential lines