The phrase "additional symbols" is correct and usable in written English.
You can use it when referring to extra characters or marks that are added to a set or collection.
Example: "In the coding language, you may need to include additional symbols to properly execute the function."
Alternatives: "extra characters" or "supplementary symbols".
Since the alphabet is notoriously inadequate for recording the sounds of English, dictionaries are forced to adopt additional symbols.
It has a syllabary of 30 consonants and five vowels; six additional symbols are used in writing Sanskrit words.
Emblazoned in the centre of the white stripe was the Lion and Sun; additional symbols (the imperial crown and a wreath) were added for special purposes such as the naval ensign.
The automatic mode adds an additional symbols to the synchronization preamble.
The 5-methyl-oxazole of AD-7075 has the additional symbols aasC and sCH3 whereas the benzo-oxazole of BRL48482 has the additional symbol aaaC.
Additional symbols used: n = peak width in channels, m = number of channels used each side of the peak to determine the continuum.
A Raptor code has the property that the decoding success probability increases with each received additional symbol.
This same person is known to make comments on Facebook at 3 or 4 AM when they can't sleep or to report that someone isn't returning their phone calls with the additional symbol of a 'sad face' using parentheses and a colon for emphasis.
When the N-terminal of a peptide is actually the N-terminal of a protein, RAId_DbS insert an additional symbol "[" in front of the peptide. An example of such is seen in the last peptide shown in Table 1.
Currently the most popular system is the R2 Image Checker, which will detect potential masses and microcalcifications and has an additional symbol for lesions with a high probability of malignancy.
For each step only two operations were allowed in the process to get the LZ complexity: either copying the longest section from the part of a nonempty sequence or generating an additional symbol mark that ensures the uniqueness of per component S(i k −1 → i k ).
