in Russian mathematical texts, normal, non-raised, ellipses are used even in repeated summations.The latter formula means the sum of all natural numbers from 1 to 100. However, it is not a formally defined mathematical symbol.
As with all characters, especially those outside the ASCII range, the author, sender and receiver of an encoded ellipsis must be in agreement upon what bytes are being used to represent the character. Naive text processing software may improperly assume that a particular encoding is being used, resulting in mojibake. In Abstract Syntax Notation One (ASN.1), the ellipsis is used as an extension marker to indicate the possibility of type extensions in future revisions of a protocol specification. In a type constraint expression like A ::= INTEGER (0..127, ..., 256..511) an ellipsis is used to separate the extension root from extension additions. The definition of type A in version 1 system of the form A ::= INTEGER (0..127, ...) and the definition of type A in version 2 system of the form A ::= INTEGER (0..127, ..., 256..511) constitute an extension series of the same type A in different versions of the same specification. The ellipsis can also be used in compound type definitions to separate the set of fields belonging to the extension root from the set of fields constituting extension additions. Here is an example: B ::= SEQUENCE { a INTEGER, b INTEGER, ..., c INTEGER }

Input
In Windows, the horizontal ellipsis can be inserted with Alt+0133, using the numeric keypad. In macOS, it can be inserted with ⌥ Opt+; (on an English language keyboard). In some Linux distributions, it can be inserted with AltGr+. (this produces an interpunct on other systems), or Compose...