diff --git a/doc/src/sgml/rangetypes.sgml b/doc/src/sgml/rangetypes.sgml
index 3a034d9b06c..b75fb3a3929 100644
--- a/doc/src/sgml/rangetypes.sgml
+++ b/doc/src/sgml/rangetypes.sgml
@@ -131,29 +131,26 @@ SELECT isempty(numrange(1, 5));
Infinite (Unbounded) Ranges
- The lower bound of a range can be omitted, meaning that all points less
- than the upper bound are included in the range. Likewise, if the upper
- bound of the range is omitted, then all points greater than the lower bound
- are included in the range. If both lower and upper bounds are omitted, all
- values of the element type are considered to be in the range.
+ The lower bound of a range can be omitted, meaning that all
+ values less than the upper bound are included in the range, e.g.,
+ (,3]. Likewise, if the upper bound of the range
+ is omitted, then all values greater than the lower bound are included
+ in the range. If both lower and upper bounds are omitted, all values
+ of the element type are considered to be in the range. Specifying a
+ missing bound as inclusive is automatically converted to exclusive,
+ e.g., [,] is converted to (,).
+ You can think of these missing values as +/-infinity, but they are
+ special range type values and are considered to be beyond any range
+ element type's +/-infinity values.
- This is equivalent to considering that the lower bound is minus
- infinity
, or the upper bound is plus infinity
,
- respectively. But note that these infinite values are never values of
- the range's element type, and can never be part of the range. (So there
- is no such thing as an inclusive infinite bound — if you try to
- write one, it will automatically be converted to an exclusive bound.)
-
-
-
- Also, some element types have a notion of infinity
, but that
- is just another value so far as the range type mechanisms are concerned.
- For example, in timestamp ranges, [today,] means the same
- thing as [today,). But [today,infinity] means
- something different from [today,infinity) — the latter
- excludes the special timestamp value infinity.
+ Element types that have the notion of infinity
can
+ use them as explicit bound values. For example, with timestamp
+ ranges, [today,infinity) excludes the special
+ timestamp value infinity,
+ while [today,infinity] include it, as does
+ [today,) and [today,].