A pair of curly braces — the workhorse group.
{ $|$ }
x^{n+1}Espanso package · 315 expansions
Every trigger in latex-quickmath, with what it means, what it expands to, and how it
sets. Triggers fire on the trailing space, so :bbR only expands once you hit the
space bar — no need to escape half-typed words.
A pair of curly braces — the workhorse group.
{ $|$ }
x^{n+1}A pair of round brackets.
( $|$ )
f(x + y)A pair of square brackets.
[ $|$ ]
\mathbb{E}[X]The empty set — the set containing no elements.
\varnothing
A \cap B = \varnothingSet literal: elements listed inside braces.
\{ $|$ \}
\{ 1, 2, 3 \}Set-builder notation: elements satisfying a condition.
\{ $|$ \mid \}
\{ x \in \mathbb{N} \mid x > 3 \}Union — everything in either set.
\cup
A \cup BUnion over a range with lower and upper bound.
\bigcup_{ $|$ }^{ }{ }
\bigcup_{i=1}^{n} A_iUnion over an index set.
\bigcup_{ $|$ }{ }
\bigcup_{i \in I} A_iIntersection — what both sets share.
\cap
A \cap BIntersection over a range with lower and upper bound.
\bigcap_{ $|$ }^{ }{ }
\bigcap_{i=1}^{n} A_iIntersection over an index set.
\bigcap_{ $|$ }{ }
\bigcap_{i \in I} A_iSet difference — in the left set but not the right.
\setminus
A \setminus BSymmetric difference — in exactly one of the two sets.
\triangle
A \triangle BCartesian product — the set of ordered pairs.
\times
A \times BDisjoint union — a union of sets known to be disjoint.
\dot\cup
A \dot\cup BCoproduct / disjoint union in the categorical sense.
\sqcup
A \sqcup BComplement as a superscript C, typed after the set.
^\mathrm{ C }
A^\mathrm{C}Overbar — complement, closure, or conjugate.
\overline{ $|$ }
\overline{A}Power set — the set of all subsets.
\mathcal{ P }( $|$ )
\mathcal{P}(A)Subset (often used loosely for ⊆).
\subset
A \subset BProper subset — contained in, but not equal to.
\subsetneq
A \subsetneq BSubset or equal — every element of A lies in B.
\subseteq
A \subseteq BSuperset (often used loosely for ⊇).
\supset
B \supset AProper superset — contains, but is not equal to.
\supsetneq
B \supsetneq ASuperset or equal — B contains every element of A.
\supseteq
B \supseteq AMembership — the element belongs to the set.
\in
x \in AReverse membership — the set contains the element.
\ni
A \ni xReverse membership; a readable alias for \ni.
\owns
A \owns xNon-membership.
\notin
x \notin AReverse non-membership.
\not\ni
A \not\ni xBlackboard P — the primes, or a probability measure.
\mathbb{ P }
p \in \mathbb{P}The natural numbers.
\mathbb{ N }
n \in \mathbb{N}The integers.
\mathbb{ Z }
\mathbb{Z} = \{ \ldots, -1, 0, 1, \ldots \}A field, typically a finite field.
\mathbb{ F }
\mathbb{F}_qThe rational numbers.
\mathbb{ Q }
\mathbb{Q} \subset \mathbb{R}The irrational numbers.
\mathbb{ I }
\mathbb{I} = \mathbb{R} \setminus \mathbb{Q}The algebraic numbers.
\mathbb{ A }
\mathbb{Q} \subset \mathbb{A}The torus, or the circle group.
\mathbb{ T }
\mathbb{T} = \mathbb{R} / \mathbb{Z}The real numbers.
\mathbb{ R }
f \colon \mathbb{R} \to \mathbb{R}The real plane.
\mathbb{ R }^2
(x, y) \in \mathbb{R}^2Real three-space.
\mathbb{ R }^3
v \in \mathbb{R}^3Real n-space, dimension left general.
\mathbb{ R }^n
x \in \mathbb{R}^nThe hyperreals of non-standard analysis.
{}^*\mathbb{ R }
{}^*\mathbb{R}The complex numbers.
\mathbb{ C }
z \in \mathbb{C}The quaternions.
\mathbb{ H }
\mathbb{H} \supset \mathbb{C}The octonions.
\mathbb{ O }
\mathbb{O} \supset \mathbb{H}A sphere, or the surreal numbers.
\mathbb{ S }
\mathbb{S}^2A generic base field, usually ℝ or ℂ.
\mathbb{ K }
V \text{ over } \mathbb{K}Universal quantifier — holds for every element.
\forall
\forall x \in \mathbb{R} \colon x^2 \geq 0Existential quantifier — at least one element works.
\exists
\exists n \in \mathbb{N} \colon n > xUnique existence — exactly one element works.
\exists!
\exists! x \colon f(x) = 0No such element exists.
\nexists
\nexists\, q \in \mathbb{Q} \colon q^2 = 2Logical and — both statements hold.
\land
p \land qLogical or — at least one statement holds.
\lor
p \lor qLogical negation.
\lnot
\lnot pConjunction over a range with bounds.
\bigwedge_{ $|$ }^{ }
\bigwedge_{i=1}^{n} p_iConjunction over an index set.
\bigwedge_{ $|$ }
\bigwedge_{i \in I} p_iDisjunction over a range with bounds.
\bigvee_{ $|$ }^{ }
\bigvee_{i=1}^{n} p_iDisjunction over an index set.
\bigvee_{ $|$ }
\bigvee_{i \in I} p_iImplication — a long arrow with proper spacing.
\implies
x > 2 \implies x^2 > 4Reverse implication — the left follows from the right.
\impliedby
x^2 = 4 \impliedby x = 2If and only if — logical equivalence.
\iff
x \geq 0 \iff |x| = xSatisfies — the structure is a model of the formula.
\models
\mathcal{M} \models \varphiProves — the formula is derivable from the theory.
\vdash
T \vdash \varphiReverse turnstile; also left adjoint to.
\dashv
F \dashv GVerum — the always-true proposition.
\top
p \lor \lnot p \iff \topFalsum — contradiction, the always-false proposition.
\bot
p \land \lnot p \iff \botTherefore — marks a conclusion.
\therefore
\therefore x = 3Because — marks a justification.
\because
\because x^2 = 9Upright “s.t.” for use inside a formula.
\text{ s.t. }
\exists n \text{ s.t. } n > xUpright “w.l.o.g.” for use inside a formula.
\text{ w.l.o.g. }
\text{ w.l.o.g. } a \leq bEnd-of-proof marker.
\blacksquare
\blacksquareNot equal.
\neq
a \neq bLess than or equal.
\leq
a \leq bGreater than or equal.
\geq
a \geq bMuch less than.
\ll
\varepsilon \ll 1Much greater than.
\gg
n \gg 0Approximately equal.
\approx
\pi \approx 3.14159Similar to, or distributed as.
\sim
X \sim \mathcal{N}(0, 1)Asymptotically or homotopically equivalent.
\simeq
a_n \simeq b_nIsomorphic or congruent.
\cong
G \cong HIdentically equal, or congruent modulo n.
\equiv
a \equiv b \pmod{n}Proportional to.
\propto
F \propto \frac{1}{r^2}Approaches, or is defined to equal.
\doteq
x \doteq yAsymptotically equivalent up to constants.
\asymp
f(n) \asymp g(n)Definition — the left side is defined by the right.
\coloneqq
S \coloneqq \{ 1, 2, 3 \}Precedes in a partial order.
\prec
a \prec bPrecedes or equals in a partial order.
\preceq
a \preceq bSucceeds in a partial order.
\succ
b \succ aSucceeds or equals in a partial order.
\succeq
b \succeq aPerpendicular, or orthogonal.
\perp
u \perp vParallel to.
\parallel
g \parallel hNot parallel to.
\nparallel
g \nparallel hDivides, or the conditioning bar in set-builder notation.
\mid
d \mid nDoes not divide.
\nmid
2 \nmid 7Maps to — the standard arrow for a function's type.
\to
f \colon X \to YSends an element to its image.
\mapsto
x \mapsto x^2Rightward arrow.
\rightarrow
a \rightarrow bLeftward arrow.
\leftarrow
a \leftarrow bTwo-way arrow.
\leftrightarrow
a \leftrightarrow bLong rightward arrow, for labelled maps.
\longrightarrow
X \longrightarrow YLong leftward arrow.
\longleftarrow
X \longleftarrow YDouble arrow — implication in a formula.
\Rightarrow
p \Rightarrow qReverse double arrow.
\Leftarrow
p \Leftarrow qDouble two-way arrow — equivalence.
\Leftrightarrow
p \Leftrightarrow qUpward arrow — increases to, or a limit from below.
\uparrow
x_n \uparrow xDownward arrow — decreases to.
\downarrow
x_n \downarrow xInjection — an embedding into a larger object.
\hookrightarrow
\mathbb{Z} \hookrightarrow \mathbb{Q}Reverse injection arrow.
\hookleftarrow
\mathbb{Q} \hookleftarrow \mathbb{Z}Surjection — the map is onto.
\twoheadrightarrow
G \twoheadrightarrow G/NSquiggly arrow — rewrites to, or leads to.
\rightsquigarrow
x \rightsquigarrow yExtensible arrow with a label above it.
\xrightarrow{ $|$ }
a_n \xrightarrow{n \to \infty} aExtensible leftward arrow with a label.
\xleftarrow{ $|$ }
X \xleftarrow{f} YExtensible maps-to arrow with a label.
\xmapsto{ $|$ }
x \xmapsto{\varphi} yCentred multiplication dot.
\cdot
a \cdot bComposition of maps, or a ring operation.
\circ
(g \circ f)(x)Asterisk operator — convolution, adjoint, or a free slot.
\ast
f \ast gStar operator — a generic binary operation.
\star
a \star bFilled bullet — a placeholder argument.
\bullet
\langle \bullet, \bullet \ranglePlus or minus.
\pm
x = 2 \pm 0.1Minus or plus — the opposite sign to a nearby ±.
\mp
a \pm b \mp cDirect sum, or exclusive or.
\oplus
V \oplus WTensor product.
\otimes
V \otimes WCircled dot — Hadamard or elementwise product.
\odot
A \odot BCentred ellipsis, for use between operators.
\cdots
a_1 + \cdots + a_nBaseline ellipsis, for use between commas.
\ldots
a_1, \ldots, a_nVertical ellipsis, for columns in a matrix.
\vdots
\vdotsDiagonal ellipsis, for a matrix diagonal.
\ddots
\ddotsDegree sign as a superscript.
^\circ
90^\circPrime mark — a derivative or a related object.
^{ \prime }
f^{\prime}(x)Colon with function-notation spacing.
\colon
f \colon X \to YOne quad of horizontal space.
\quad
a = b \quad \text{for all } xTwo quads of horizontal space.
\qquad
a = b \qquad c = dThin space — fine spacing adjustment.
\,
\mathbb{R}\,^nAlpha — angles, coefficients, significance levels.
\alpha
\alpha + \beta = \piBeta — a second angle or coefficient.
\beta
\beta_1 x + \beta_0Gamma — the gamma function, curves, Euler's constant.
\gamma
\gamma \approx 0.5772Delta — a small change, or the Kronecker delta.
\delta
\delta_{ij}Epsilon — a small positive quantity (lunate form).
\epsilon
\epsilon > 0Varepsilon — the form most analysts prefer.
\varepsilon
|x - a| < \varepsilonZeta — the Riemann zeta function.
\zeta
\zeta(s) = \sum_{n=1}^{\infty} n^{-s}Eta — efficiency, or a learning rate.
\eta
\eta \in (0, 1)Theta — angles and parameter vectors.
\theta
\cos \thetaVartheta — the script form of theta.
\vartheta
\varthetaIota — an inclusion map.
\iota
\iota \colon A \hookrightarrow BKappa — curvature or a condition number.
\kappa
\kappa(A)Lambda — eigenvalues, rates, Lebesgue measure.
\lambda
A v = \lambda vMu — a mean, or a measure.
\mu
\mu = \mathbb{E}[X]Nu — a second measure, or degrees of freedom.
\nu
\nu \ll \muXi — a random variable or auxiliary point.
\xi
\xi \in [a, b]Pi — the circle constant, or a projection.
\pi
\pi r^2Varpi — the variant form of pi.
\varpi
\varpiRho — density, correlation, spectral radius.
\rho
\rho(X, Y)Varrho — the variant form of rho.
\varrho
\varrhoSigma — standard deviation, or a σ-algebra.
\sigma
\sigma^2 = \operatorname{Var}(X)Varsigma — final sigma, used as a variant.
\varsigma
\varsigmaTau — time constants, torsion, Kendall's tau.
\tau
\tau = 2\piUpsilon.
\upsilon
\upsilonPhi — the golden ratio, Euler's totient, angles.
\phi
\phi(n)Varphi — the looped form, common for maps.
\varphi
\varphi \colon G \to HChi — characters and the chi-squared distribution.
\chi
\chi^2Psi — wave functions and digamma.
\psi
\psi(x)Omega — frequency, the first infinite ordinal.
\omega
\omega = e^{2\pi i / n}Capital gamma — the gamma function, or a contour.
\Gamma
\Gamma(n+1) = n!Capital delta — a difference, or the Laplacian.
\Delta
\Delta x \to 0Capital theta — tight asymptotic growth.
\Theta
\Theta(n \log n)Capital lambda — a diagonal matrix of eigenvalues.
\Lambda
A = Q \Lambda Q^{-1}Capital xi.
\Xi
\XiCapital pi — a product, or a projection.
\Pi
\Pi_{i}Capital sigma — a sum, or a covariance matrix.
\Sigma
\Sigma = \operatorname{Cov}(X)Capital upsilon.
\Upsilon
\UpsilonCapital phi — the normal CDF, or a map.
\Phi
\Phi(z)Capital psi.
\Psi
\PsiCapital omega — the sample space, or a domain.
\Omega
\omega \in \OmegaScript ell — sequence spaces and lengths.
\ell
\ell^2(\mathbb{N})Reduced Planck constant.
\hbar
\hbar = \frac{h}{2\pi}Aleph — infinite cardinal numbers.
\aleph
\aleph_0Beth — the beth cardinals.
\beth
\beth_1 = 2^{\aleph_0}Infinity.
\infty
\lim_{n \to \infty} a_nLimit with a subscript condition.
\lim_{ $|$ }
\lim_{x \to 0} \frac{\sin x}{x} = 1Limit with the arrow already in place.
\lim_{ $|$ \to }
\lim_{n \to \infty} \frac{1}{n} = 0Limit superior — the largest accumulation point.
\limsup_{ $|$ }
\limsup_{n \to \infty} a_nLimit inferior — the smallest accumulation point.
\liminf_{ $|$ }
\liminf_{n \to \infty} a_nSupremum — the least upper bound.
\sup_{ $|$ }
\sup_{x \in A} f(x)Infimum — the greatest lower bound.
\inf_{ $|$ }
\inf_{x \in A} f(x)Maximum — an attained largest value.
\max
\max \{ a, b \}Minimum — an attained smallest value.
\min
\min \{ a, b \}The argument at which a maximum is attained.
\operatorname*{ arg\,max }_{ $|$ }
\operatorname*{arg\,max}_{x \in A} f(x)The argument at which a minimum is attained.
\operatorname*{ arg\,min }_{ $|$ }
\operatorname*{arg\,min}_{\theta} L(\theta)Sum with lower and upper bounds.
\sum_{ $|$ }^{ }
\sum_{i=1}^{n} a_iSum over an index set.
\sum_{ $|$ }
\sum_{i \in I} a_iInfinite series — the upper bound is already ∞.
\sum_{ $|$ }^{ \infty }
\sum_{n=0}^{\infty} \frac{1}{n!} = eProduct with lower and upper bounds.
\prod_{ $|$ }^{ }
\prod_{i=1}^{n} a_iProduct over an index set.
\prod_{ $|$ }
\prod_{p \in \mathbb{P}} pDefinite integral with both limits.
\int_{ $|$ }^{ }
\int_{0}^{1} x^2 \, \mathrm{d}xIntegral over a domain rather than an interval.
\int_{ $|$ }
\int_{\Omega} f \, \mathrm{d}\muContour integral around a closed curve.
\oint_{ $|$ }
\oint_{\gamma} f(z) \, \mathrm{d}zDouble integral over a region.
\iint_{ $|$ }
\iint_{D} f(x, y) \, \mathrm{d}ATriple integral over a volume.
\iiint_{ $|$ }
\iiint_{V} \rho \, \mathrm{d}VUpright differential d with its thin space.
\, \mathrm{ d }
\int f(x) \, \mathrm{d}xOrdinary derivative as a fraction.
\frac{ \mathrm{ d } $|$ }{ \mathrm{ d } }
\frac{\mathrm{d}y}{\mathrm{d}x}Partial derivative as a fraction.
\frac{ \partial $|$ }{ \partial }
\frac{\partial f}{\partial x}Partial derivative symbol, also a boundary.
\partial
\partial \OmegaNabla — gradient, divergence, or curl.
\nabla
\nabla fFraction with numerator and denominator.
\frac{ $|$ }{ }
\frac{a}{b}Square root.
\sqrt{ $|$ }
\sqrt{x^2 + y^2}nth root — the index goes in the brackets.
\sqrt[ $|$ ]{ }
\sqrt[3]{x}Binomial coefficient.
\binom{ $|$ }{ }
\binom{n}{k}Exponential function with parentheses ready.
\exp( $|$ )
\exp(x + y)Natural logarithm.
\ln
\ln e = 1Logarithm with a subscript base.
\log_{ $|$ }
\log_{2} nSine.
\sin
\sin^2 x + \cos^2 x = 1Cosine.
\cos
\cos(2x)Tangent.
\tan
\tan x = \frac{\sin x}{\cos x}Big-O — an asymptotic upper bound.
\mathcal{ O }( $|$ )
\mathcal{O}(n \log n)Little-o — strictly smaller asymptotic growth.
\mathrm{ o }( $|$ )
\mathrm{o}(n)Determinant.
\det
\det(A) \neq 0Trace — the sum of the diagonal entries.
\operatorname{ tr }
\operatorname{tr}(A) = \sum_i a_{ii}Rank — the dimension of the image.
\operatorname{ rank }
\operatorname{rank}(A) = nDimension of a vector space.
\dim
\dim V = nSpan — all linear combinations of the given vectors.
\operatorname{ span }( $|$ )
\operatorname{span}(v_1, v_2)Kernel — the vectors sent to zero.
\ker
\ker(f) = \{ 0 \}Image — the set of values actually attained.
\operatorname{ im }
\operatorname{im}(f) \subseteq WDiagonal matrix built from the listed entries.
\operatorname{ diag }( $|$ )
\operatorname{diag}(\lambda_1, \lambda_2)Projection onto a subspace.
\operatorname{ proj }_{ $|$ }
\operatorname{proj}_{U}(v)Identity map or identity matrix.
\mathrm{ id }
f \circ f^{-1} = \mathrm{id}Transpose, as an upright sans-serif superscript T.
^\mathsf{ T }
A^\mathsf{T} AInverse as a −1 superscript.
^{ -1 }
A^{-1} A = IDagger — conjugate transpose or adjoint.
^\dagger
A^\daggerInner product of two vectors.
\langle $|$ , \rangle
\langle u, v \rangle = 0The set of homomorphisms between two objects.
\operatorname{ Hom }( $|$ , )
\operatorname{Hom}(V, W)Endomorphisms — homomorphisms of an object to itself.
\operatorname{ End }( $|$ )
\operatorname{End}(V)The automorphism group.
\operatorname{ Aut }( $|$ )
\operatorname{Aut}(G)General linear group — invertible matrices.
\operatorname{ GL }_{ $|$ }( )
\operatorname{GL}_{n}(\mathbb{R})Special linear group — determinant one.
\operatorname{ SL }_{ $|$ }( )
\operatorname{SL}_{2}(\mathbb{Z})Symmetric group on n letters.
\mathfrak{ S }_{ $|$ }
\mathfrak{S}_{n}Normal subgroup, or a two-sided ideal.
\trianglelefteq
N \trianglelefteq GSemidirect product, normal factor on the left.
\rtimes
N \rtimes HSemidirect product, normal factor on the right.
\ltimes
H \ltimes NThe integers modulo n.
\mathbb{ Z } / $|$ \mathbb{ Z }
\mathbb{Z} / n \mathbb{Z}Binary mod operator inside an expression.
\bmod
a \bmod nParenthesised modulus after a congruence.
\pmod{ $|$ }
a \equiv b \pmod{n}Unit group, written as a × superscript.
^\times
R^\timesIsomorphism arrow with a tilde above it.
\xrightarrow{ \sim }
V \xrightarrow{\sim} WOrder of a group element.
\operatorname{ ord }( $|$ )
\operatorname{ord}(g) = 6Characteristic of a ring or field.
\operatorname{ char }( $|$ )
\operatorname{char}(\mathbb{F}_p) = pDegree of a polynomial or field extension.
\deg
\deg f = 3Greatest common divisor.
\gcd
\gcd(a, b) = 1Least common multiple.
\operatorname{ lcm }
\operatorname{lcm}(4, 6) = 12Probability of an event.
\mathbb{ P }( $|$ )
\mathbb{P}(A \cup B)Conditional probability, bar already in place.
\mathbb{ P }( $|$ \mid )
\mathbb{P}(A \mid B)Expected value.
\mathbb{ E }[ $|$ ]
\mathbb{E}[X]Conditional expectation.
\mathbb{ E }[ $|$ \mid ]
\mathbb{E}[X \mid \mathcal{F}]Variance.
\operatorname{ Var }( $|$ )
\operatorname{Var}(X) = \sigma^2Covariance of two random variables.
\operatorname{ Cov }( $|$ , )
\operatorname{Cov}(X, Y)Normal distribution with mean and variance.
\mathcal{ N }( $|$ , )
X \sim \mathcal{N}(\mu, \sigma^2)Borel σ-algebra on a space.
\mathcal{ B }( $|$ )
\mathcal{B}(\mathbb{R})A σ-algebra of events.
\mathcal{ F }
A \in \mathcal{F}A complete probability space triple.
( \Omega, \mathcal{ F }, \mathbb{ P } )
( \Omega, \mathcal{F}, \mathbb{P} )Independent and identically distributed.
\overset{ \text{i.i.d.} }{ \sim }
X_i \overset{\text{i.i.d.}}{\sim} FIndependent of.
\perp\!\!\!\perp
X \perp\!\!\!\perp YAlmost surely — with probability one.
\text{ a.s. }
X_n \to X \text{ a.s. }Convergence in distribution.
\xrightarrow{ d }
X_n \xrightarrow{d} XConvergence in probability.
\xrightarrow{ \mathbb{ P } }
X_n \xrightarrow{\mathbb{P}} XAlmost sure convergence.
\xrightarrow{ \text{a.s.} }
X_n \xrightarrow{\text{a.s.}} XHat — an estimator or a unit vector.
\hat{ $|$ }
\hat{\theta}Wide hat, for expressions longer than one symbol.
\widehat{ $|$ }
\widehat{ABC}Bar — a mean, closure, or conjugate.
\bar{ $|$ }
\bar{x} = \frac{1}{n} \sum_i x_iTilde — a modified version of an object.
\tilde{ $|$ }
\tilde{f}Wide tilde, for longer expressions.
\widetilde{ $|$ }
\widetilde{XYZ}Vector arrow.
\vec{ $|$ }
\vec{v} \cdot \vec{w}Single dot — the first time derivative.
\dot{ $|$ }
\dot{x}(t)Double dot — the second time derivative.
\ddot{ $|$ }
\ddot{x} = -\omega^2 xUnderline.
\underline{ $|$ }
\underline{a}Brace below an expression with a label under it.
\underbrace{ $|$ }_{ }
\underbrace{a + \cdots + a}_{n \text{ times}}Brace above an expression with a label over it.
\overbrace{ $|$ }^{ }
\overbrace{x + y}^{s}Places the first argument above the second.
\overset{ $|$ }{ }
\overset{!}{=}Places the first argument below the second.
\underset{ $|$ }{ }
\underset{n \to \infty}{\lim}Subscript group.
_{ $|$ }
a_{ij}Superscript group — powers and indices.
^{ $|$ }
x^{n+1}Upright prose inside a formula.
\text{ $|$ }
x > 0 \text{ for all } xUpright roman — units and multi-letter names.
\mathrm{ $|$ }
\mathrm{d}xBold — vectors and matrices.
\mathbf{ $|$ }
\mathbf{A} \mathbf{x}Math italic.
\mathit{ $|$ }
\mathit{diff}Sans-serif — categories, or the transpose T.
\mathsf{ $|$ }
\mathsf{Set}Monospace.
\mathtt{ $|$ }
\mathtt{code}Calligraphic — σ-algebras, categories, Landau O.
\mathcal{ $|$ }
\mathcal{F}Fraktur — Lie algebras, ideals, prime ideals.
\mathfrak{ $|$ }
\mathfrak{g}Blackboard bold, for any letter not in the list above.
\mathbb{ $|$ }
\mathbb{X}Absolute value, using proper vertical delimiters.
\lvert $|$ \rvert
\lvert x - y \rvertNorm of a vector or function.
\lVert $|$ \rVert
\lVert x \rVert_2Floor — round down to an integer.
\lfloor $|$ \rfloor
\lfloor 3.7 \rfloor = 3Ceiling — round up to an integer.
\lceil $|$ \rceil
\lceil 3.2 \rceil = 4Angle brackets — a generated object or a bra-ket.
\langle $|$ \rangle
\langle g \rangleAuto-sized parentheses.
\left( $|$ \right)
\left( \frac{a}{b} \right)Auto-sized braces.
\left\{ $|$ \right\}
\left\{ \frac{a}{b} \right\}Auto-sized square brackets.
\left[ $|$ \right]
\left[ \frac{a}{b} \right]Auto-sized absolute value bars.
\left\lvert $|$ \right\rvert
\left\lvert \frac{a}{b} \right\rvertAuto-sized norm bars.
\left\lVert $|$ \right\rVert
\left\lVert \frac{a}{b} \right\rVertAuto-sized angle brackets.
\left\langle $|$ \right\rangle
\left\langle \frac{a}{b} \right\rangleA divider that grows with its surrounding delimiters.
\middle|
\left\{ x \middle| \frac{x}{2} \in \mathbb{Z} \right\}Evaluation bar, for substituting a bound.
\left. $|$ \right|_{ }
\left. F(x) \right|_{0}^{1}A single numbered display equation.
\begin{equation}
$|$
\end{equation}
\begin{equation}
E = mc^2
\end{equation}Multi-line equations aligned at the & marks, numbered.
\begin{align}
$|$
\end{align}
\begin{align}
(a+b)^2 &= a^2 + 2ab + b^2 \\
&= a^2 + b^2 + 2ab
\end{align}The same alignment, without equation numbers.
\begin{align*}
$|$
\end{align*}
\begin{align*}
f(x) &= x^2 \\
f'(x) &= 2x
\end{align*}Several centred equations, each on its own line.
\begin{gather}
$|$
\end{gather}
\begin{gather}
a = b \\
c = d
\end{gather}A case distinction with conditions on the right.
\begin{cases}
$|$ & \text{if } \\
& \text{else}
\end{cases}
\begin{cases}
x & \text{if } x \geq 0 \\
-x & \text{else}
\end{cases}A matrix body with no delimiters.
\begin{matrix}
$|$
\end{matrix}
\begin{matrix}
a & b \\
c & d
\end{matrix}Matrix in round brackets — the usual choice.
\begin{pmatrix}
$|$
\end{pmatrix}
\begin{pmatrix}
a & b \\
c & d
\end{pmatrix}Matrix in square brackets.
\begin{bmatrix}
$|$
\end{bmatrix}
\begin{bmatrix}
a & b \\
c & d
\end{bmatrix}Single bars — a determinant.
\begin{vmatrix}
$|$
\end{vmatrix}
\begin{vmatrix}
a & b \\
c & d
\end{vmatrix}Double bars — an operator norm.
\begin{Vmatrix}
$|$
\end{Vmatrix}
\begin{Vmatrix}
a & b \\
c & d
\end{Vmatrix}A tiny matrix that fits inside a line of text.
\begin{smallmatrix} $|$ \end{smallmatrix}
\begin{smallmatrix} a & b \\ c & d \end{smallmatrix}A general table, with a column specification.
\begin{array}{ $|$ }
\end{array}
\begin{array}{cc}
a & b \\
c & d
\end{array}Nothing matches that. Try a symbol name, a LaTeX command, or a word from a description.