The letter ℘: name and origin? (2017)

Original Article ↗ Hacker News Discussion ↗

Difficulty of Learning Mathematical Symbols

  • Many commenters struggle to read math when they can’t “say” a symbol; unfamiliar glyphs block parsing.
  • Abstract squiggles (e.g., ℘, ξ, ζ) are hard to name, look up, or remember, especially from non-digital sources.
  • Some recall discovering only later that familiar constructs like “dx/dt” behave algebraically, revealing how symbolic “tokens” can obscure meaning.

Tools and Methods to Identify Symbols

  • Drawing-based tools like Detexify and Shapecatcher are praised for mapping sketches to LaTeX/Unicode symbols.
  • Unicode utilities (e.g., command-line programs or PDFs of symbol charts) help once you can copy/paste the character.
  • Vision and text LLMs are now viewed as practical “symbol lookup” tools, though results can be hit-or-miss.

Notation Conventions and Overload

  • There’s appreciation for books with “tables of symbols” and dependency maps; lack of this is seen as a barrier.
  • Complaints focus on:
    • Overuse of single letters with font-based semantics (bold, blackboard bold, Fraktur, script).
    • Ambiguous or nearly indistinguishable glyphs (e.g., nu vs v, Xi vs its conjugate with bars).
    • Proliferation of stylistic variants with distinct Unicode codepoints.
  • Others defend this ecosystem as a compact, time-tested shorthand that supports abstraction and reusability.

Unicode, ℘, and Historical Context

  • Unicode labels ℘ as “SCRIPT CAPITAL P” (U+2118), but commenters note it is functionally a special lowercase symbol used for the Weierstrass elliptic function.
  • Technical notes are cited stating the intended alias “WEIERSTRASS ELLIPTIC FUNCTION.”
  • Discussion links its shape to historical German scripts (Fraktur/Sütterlin) and broader script politics, but the exact influence on notation is acknowledged as uncertain.

Comparisons to Programming Languages

  • Some argue programming notation (ASCII identifiers like sum) is more searchable and self-explanatory than mathematical symbols like Σ.
  • Others counter that programming is equally arcane, with its own dense shorthands and symbolic operators; restricting alphabets doesn’t guarantee clarity.