New posts in Content Replication

How do you reprint a theorem, proposition, etc. in its entirety?

Can I introduce a special environment which will reappear at the end?

Transform existing text into blind text or gibberish keeping format (wireframing)

Using a figure again in document

List of equations, including equation contents and caption

copy and reuse the content of an environment

Collecting contents of environment and store them for later retrieval

Define reusable content --- preferably in the body or else in the header

Filecontents and newenvironment issue

Is it possible to write all mathematical formulas in a separate file and add them in main file on-demand?