Mathematical Script Capital G

The author defines it; 𝒢 has no universal meaning.

A calligraphic letter gives mathematical writing another alphabet, much like bold and italic letters do. Unicode encoded these styles separately so plain text can preserve mathematical distinctions; the script style alone does not tell you which object an author means.

For example, \mathcal{G} can label a graph; another author may assign it a different role.

How do I enter the exact Unicode character?

Use \mathcal{G} to typeset; use Unicode hex for 𝒢 itself.

LaTeX is a math typesetting system: in math mode, \mathcal{G} styles the ordinary Latin letter G. It may look like 𝒢 in a PDF without containing this standalone Unicode character. Hex entry inserts the encoded character itself.

Why does 𝒢 look different across fonts?

Math fonts draw this calligraphic letter in different hands.

Roundhand and chancery are two handwriting-inspired calligraphic styles. The Unicode 18.0 chart uses roundhand, while Cambria Math and STIX Two Math default to chancery.

Mathematical writing usually treats the two hands as interchangeable, but Unicode 14.0 added variation selectors for cases where the distinction matters: U+FE00 requests chancery, and U+FE01 requests roundhand.