## SET-CHECKPOINT-SUMMARY-LIMIT

control printing of key checkpoints upon a proof's failure
```Major Section:  SWITCHES-PARAMETERS-AND-MODES
```

See set-gag-mode for a discussion of key checkpoints.

```Examples:

; (Default) When a proof fails, print all key checkpoints before
; induction but at most 3 key checkpoints after induction:
(set-checkpoint-summary-limit (nil . 3))

; When a proof fails, print at most 3 key checkpoints before
; induction but all 3 key checkpoints after induction:
(set-checkpoint-summary-limit (3 . nil))

; When a proof fails, print at most 3 key checkpoints before
; induction and at most 5 key checkpoints after induction:
(set-checkpoint-summary-limit (3 . 5))

; When a proof fails, print at most 3 key checkpoints before
; induction and at most 3 key checkpoints after induction:
(set-checkpoint-summary-limit (3 . 3))
; or equivalently,
(set-checkpoint-summary-limit 3)

; When a proof fails, print all key checkpoints:
(set-checkpoint-summary-limit (nil . nil))
; or equivalently,
(set-checkpoint-summary-limit nil)

; When a proof fails, print no information at all about key checkpoints:
(set-checkpoint-summary-limit t)

General Forms:
(set-checkpoint-summary-limit (n1 . n2))
(set-checkpoint-summary-limit n)
(set-checkpoint-summary-limit t)
```
where each of `n1` and `n2` is a natural number or `nil`. For the second form, `n` can be a natural number or `nil` and is treated as `(n . n)`. The value `t` inhibits all printing of checkpoint summary information. The values `n1` and `n2` determine printing of key checkpoints generated before the first induction and generated after the first induction, respectively, where at most `n1` or `n2` (respectively) such key checkpoints are printed unless the value is `nil`, in which case there is no limitation.

The argument `x` for `set-checkpoint-summary-limit`, as described above, may be quoted, i.e. supplied as `'x` or `(quote x)`. Thus, you may use the keyword form (see keyword-commands) if you prefer, for example:

```:set-checkpoint-summary-limit (nil . 3)
```