This skill must be used whenever a response needs mathematical notation — equations, filters, set-builder notation, statistics, calculus, linear algebra, logic, ratios, drops, or counts. Load it before composing, including when the user explicitly mentions math-unicode. Emit terminal-native Unicode inline, never raw LaTeX delimiters or commands.
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This skill must be used whenever a response needs mathematical notation — equations, filters, set-builder notation, statistics, calculus, linear algebra, logic, ratios, drops, or counts. Load it before composing, including when the user explicitly mentions math-unicode. Emit terminal-native Unicode inline, never raw LaTeX delimiters or commands.
disable-model-invocation
false
math-unicode
When emitting mathematical notation in a terminal coding agent (Claude Code, Codex CLI, or similar), always use Unicode glyphs inline — never wrap math in $…$, \(...\), or $$...$$. These terminals do not render LaTeX; raw delimiters appear as plain dollar signs and reduce readability.
Bad: The filter $f(T; m) = \{(s,r) : n_{s,r} \geq m\}$ produces the cohort.
Good: The filter f(T; m) = { (s,r) : n_{s,r} ≥ m } produces the cohort.
Rule 2 — Block math: own line(s), still no delimiters
Bad:
$$|Q| / |T| = 5238 / 31075 \approx 16.9\%$$
Good:
|Q| / |T| = 5 238 / 31 075 ≈ 16.9 %
Rule 3 — Subscripts
Single Unicode-renderable index: prefer the glyph (x₁, x₂, xᵢ, xⱼ, xₙ).
Single index with no subscript glyph: use a bare underscore — I_ν, ∂_μ.
Multi-character or grouped subscript: use _{...} syntax — the underscore
reads unambiguously as a subscript and stays more legible than bracket-style
indexing:
n_{s,r} ← (s,r) has no Unicode subscript form
x_max, σ_obs ← multi-letter
Never mix: don't write x_₁ or x_{1} when x₁ works.
Rule 4 — Superscripts (powers)
Simple / Unicode-mappable exponent: prefer the glyph — x², x³, xⁿ, eˣ, A⁻¹,
and the transpose xᵀ / vᵀ.
Single exponent with no glyph: use a bare caret — x^ν, (z/2)^a.
Multi-character or expression exponent: use caret + parentheses, never
^{...} — x^(k+1), x^(i), e^(iπ). A bare x^{T} / x^{(i)} leaks
LaTeX source; write xᵀ (single glyph) or x^(i) (parenthesized).
Rule 5 — Big operators with selectors
Unicode operator + a bracketed inline selector — never _{...}^{...}. Use
.. for a numeric/expression range, ∈ for set membership, → for a limit
target, and an equation/condition when that is the natural selector:
Use ordinary letters for named functions: Γ, B, erf, det, tr, Re,
Im, exp, log, sin, cos, argmin. Do not emit \operatorname.
For a left-scripted named function, use available glyphs such as ₂F₁(a,b;c;z);
when an index cannot be expressed as one glyph, use readable ASCII notation such
as _{p}F_q rather than inventing a substitute.
Rule 6 — Fractions
Inline: a/b, (a + b) / (c + d)
Block (only when it aids clarity):
a + b
─────────────
c² + d²
Rule 7 — Matrices / vectors
ASCII art with corner glyphs:
A = ⎡ a b ⎤ v = ( v₁ , v₂ , v₃ )ᵀ
⎣ c d ⎦
Declare variable types in prose instead of faking bold or italic: “Here z and n
are vectors, and Ω is a matrix.”
Rule 8 — Tensor indices
Tensor indices are indices, not powers. Keep non-mappable tensor indices in
bare ASCII form and group only when the index has multiple characters:
R^ρ_{σμν} ∂_μ Γ^ρ_{νσ}
Rule 9 — Piecewise forms and aligned derivations
Use the box-drawing brace glyphs for a short piecewise definition; keep equals
signs in the same column for a derivation. If those brace glyphs are absent in a
reader's font, use a semicolon-separated sentence instead.
f(x) =
⎧ x² if x ≥ 0
⎩ −x if x < 0
aₙ = bₙ + cₙ
= dₙ
Rule 10 — Sets and conditions
Prefer set-builder with | or ::
Q = { (s,r) ∈ T : n_{s,r} ≥ 18 ∧ p⁰_{s,r} < 0.9 }
Rule 11 — Numbers
Thousands: thin space (, U+2009) — 5 238, 34 601 — not commas (locale ambiguous).
Decimal: dot — 16.9 %.
Percent: space before % — 16.9 % (typographic convention; readable).
Approximations: ≈, ∼. Order of magnitude: ~. Confidence: x = 5.2 ± 0.3.
Rule 12 — When Unicode hurts, fall back explicitly
If a glyph chain becomes denser than the LaTeX it replaces, switch to readable ASCII pseudo-LaTeX and annotate it. Example:
H(p) = − ∑[x ∈ X] p(x) · log p(x) (∑ = sum over the support X)
The reader's comprehension is the only metric. Prefer common, well-supported
glyphs. Do not use combining marks or obscure modifier letters just to force a
super- or subscript; use readable bare ^x / _x notation instead. Choose
whichever form is clearest, then stay consistent within a passage.
Rule 13 — Plain letters for variables; never style with math-alphanumeric codepoints
Write variable names and identifiers with ordinary letters (x, A, Var, RSS). Do not reach into the Unicode Mathematical Alphanumeric Symbols block (𝐀 bold, 𝐴 italic, 𝓐 script, 𝔸 styled double-struck) to style ordinary letters. Those codepoints garble on copy/paste, terminal search, and screen readers — the same failure Claude Code hit in issue #61558.
Exception: the standard, semantically meaningful blackboard-bold sets and operators are correct notation, not styling — keep using ℕ ℤ ℚ ℝ ℂ ℙ 𝔽 (number sets) and 𝔼 (expectation). Use those; don't hand-style anything else.
Quick reference — common forms
Mean / std μ ± σ x̄ ± s
Probability P(A | B) ℙ(A ∩ B) = ℙ(A) · ℙ(B | A)
Expectation 𝔼[X] = ∫ x · f(x) dx
Variance Var(X) = 𝔼[X²] − 𝔼[X]²
Gradient ∇f = ( ∂f/∂x₁ , ... , ∂f/∂xₙ )
Norm ‖x‖₂ = √(∑[i=1..n] xᵢ²)
Big-O T(n) = O(n log n)
Limit lim[n → ∞] aₙ = L
Sum bounds ∑[i=1..n] i = n(n+1)/2
Quantile q_α = inf{ x : F(x) ≥ α }
Golden corpus — difficult terminal-native forms
These examples are deliberately chosen to exercise non-mappable indices,
constrained sums, tensors, special functions, contours, and multiline output.
They are normalized terminal forms of standard formulas (including DLMF
§10.32.E2, §15.6.E1, §19.19.E1, and §21.2.E1).
I_ν(z) = (z/2)^ν / (√π Γ(ν+½)) ∫[0..π] e^(±z cos θ)(sin θ)^(2ν) dθ
F(a,b;c;z) = 1 / (Γ(b)Γ(c−b)) ∫[0..1] t^(b−1)(1−t)^(c−b−1) / (1−zt)^a dt
T_N(b,z) = ∑[m₁+...+mₙ=N] ((b₁)_{m₁} ··· (bₙ)_{mₙ}) / (m₁! ··· mₙ!) · z₁^(m₁) ··· zₙ^(mₙ)
θ(z | Ω) = ∑[n ∈ ℤ^g] exp(2π i(½ n · Ω · n + n · z))
Here z and n are vectors, and Ω is a matrix.
R^ρ_{σμν} = ∂_μ Γ^ρ_{νσ} − ∂_ν Γ^ρ_{μσ} + Γ^ρ_{μλ} Γ^λ_{νσ} − Γ^ρ_{νλ} Γ^λ_{μσ}
f^(n)(z₀) = n! / (2π i) ∮[C] f(z) / (z−z₀)^(n+1) dz
∂u/∂t + (u · ∇)u = −∇p + νΔu + f, ∇·u = 0
p(x) = exp(−½ (x−μ)ᵀΣ⁻¹(x−μ)) / √((2π)ᵈ det Σ)
F(ω) = ∫[−∞..∞] f(t)e^(−iωt) dt
f(x) =
⎧ x² if x ≥ 0
⎩ −x if x < 0
Anti-patterns — never emit these in the terminal (Claude Code / Codex)
✗ $f(x) = \sum_{i=1}^{n} x_i$
✗ \( a^2 + b^2 = c^2 \)
✗ $$\int_0^\infty e^{-x^2} dx = \frac{\sqrt{\pi}}{2}$$
✗ \[ |Q|/|T| \approx 16.9\% \]
✗ ∑_{i=1}^{n} or ∫_a^b or x^{T} (stacked bounds / brace exponent leak source even without $…$ — write ∑[i=1..n], ∫[a..b], xᵀ)
✗ Let 𝑉𝑎𝑟 = … or matrix 𝐀 = … (math-alphanumeric styling; garbles on copy/search — write Var, A)
If asked to produce raw LaTeX (e.g. for a .tex file or a KaTeX-rendering tool downstream), do so — and call it out explicitly: "Raw LaTeX as requested; this will not render in the terminal."
