(1- 3) Notation in Elisp

Question

I'm not sure what (1- 3) means in Elisp, as I'm only used to seeing operators, or more appropriately "functions," as the first argument in the list, such as (- 1 3), not following a value, as in (1- 3). Thanks.

Answer 1

1+ and 1- are function names (so you can use C-h f to read about them).

(1+ n) returns n + 1.

(1- n) returns n - 1.

The latter can be confusing to read if you don't know what's going on, granted.