This command defines a theorem-like environment.
The \newtheorem command may have at most one optional argument.
- env_name The name of the environment -- a string of letters.
Must not be the name of an existing environment or counter.
- caption The text printed at the beginning of the environment,
right before the number.
- within The name of an already defined counter, usually of a
sectional unit. Provides a means of resetting the new theorem
counter within the sectional unit.
- numbered_like The name of an already defined theorem-like