Entering unicode math symbols into LaTeX, direct from keyboard, on a Mac

Question

I would like my LaTeX files to contain Unicode characters. For instance, I want to see

∃x．x ⟶ β

in my text editor, rather than

\exists x\ldotp x\longrightarrow\beta

Also, I would like to type these characters directly from my keyboard. For instance, I want

• to get "∃" by typing altE,
• to get "β" by typing altb, and
• to get "⟶" by typing alt-->.

I'm running Mac OS X, and my keyboard has a British layout.

Answer 1

There are two separate tasks here: making your keyboard produce the various Unicode symbols, and making those symbols meaningful to LaTeX.

1. Producing Unicode symbols from your keyboard

If you're on a Mac, make a .keylayout file, put it in the ~/Library/Keyboard Layouts directory, then log out and back in again. Your new keyboard layout should now appear in System Preferences > Language & Text > Input Sources.

But how does one create this keylayout? I used an editor (such as Ukelele) but also ended up doing quite a bit of tweaking by hand. Keylayouts are written in XML, following Apple's specification. My keylayout is called MathUnicode.keylayout, and can be downloaded here. It is based on the British keylayout. I have given my keylayout a custom icon by saving MathUnicode.icns(which can be downloaded here) in the same directory.

I list below all of the key bindings in my layout. Note that, for instance, alt--> (which produces ⟶) means "type --> while holding down the alt key". Note also that I have generally avoided notating the shift key (preferring P over shiftp, and so on) except where it makes the mnemonic more memorable.

---

α (alpha) alta

β (beta) altb

γ (gamma) altg

Γ (Gamma) altG

δ (delta) altd

Δ (Delta) altD

ε (epsilon) alte

ζ (zeta) altz

η (eta) alth

θ (theta) alto

Θ (Theta) altO

ι (iota) alti

κ (kappa) altk

λ (lambda) altl

Λ (Lambda) altL

μ (mu) altm

ν (nu) altn

ξ (xi) altx

Ξ (Xi) altX

π (pi) altp

Π (Pi) altP

ρ (rho) altr

σ (sigma) alts

Σ (Sigma) altS

τ (tau) altt

υ (upsilon) altu

φ (phi) (altf

Φ (Phi) altF

χ (chi) altc

ψ (psi) alty

Ψ (Psi) altY

ω (omega) altw

Ω (Omega) altW

---

ℂ (complex numbers) altC

ℕ (naturals) altN

ℚ (rationals) altQ

ℝ (reals) altR

ℤ (integers) altZ

---

” (closing double quotes) alt'

“ (opening double quotes) alt`

¶ (paragraph) alt§

° (degrees) alt±

… (ellipsis) alt;

---

⌊ (lower left bracket) alt[

⌋ (lower right bracket) alt]

⌈ (upper left bracket) altshift[

⌉ (upper right bracket) altshift]

〈 (left angled bracket) alt<

〉(right angled bracket) alt>

⟦ (double left bracket) alt|[

⟧ (double right bracket) alt|]

---

↑ (up arrow) alt6

↓ (down arrow) alt7

⇑ (double up arrow) altshift6

⇓ (double down arrow) altshift7

← (left arrow) alt<-

→ (right arrow) alt->

↔ (left right arrow) alt<->

⇐ (double left arrow) alt<=

⇒ (double right arrow) alt=>

⇔ (double left right arrow) alt<=>

⟵ (long left arrow) alt<--

⟶ (long right arrow) alt-->

⟷ (long left right arrow) alt<-->

⟸ (long double left arrow) alt<==

⟹ (long double right arrow) alt==>

⟺ (long double left right arrow) alt<==>

↦ (maps-to) alt|->

⤇ (double maps-to) alt|=>

⟼ (long maps-to) alt|-->

⟾ (long double maps-to) alt|==>

⇀ (right harpoon) alt--`

⇝ (squiggly right arrow) alt~>

---

¬ (logical not) alt~

∨ (logical disjunction) alt\

∧ (logical conjunction) alt/\

∀ (for all) altA

∃ (exists) altE

∄ (does not exist) alt/E

．(ldotp, the dot in ∃x. p) alt,

⊦ (turnstile) alt|-

⊩ (double turnstile) alt||-

⊧ (models) alt|=

⟂ (bottom) alt _ | or alt| _

---

∅ (empty set) alt/0

∈ (member of) alt:

∉ (not member of) alt/:

∪ (union) altU

∩ (intersection) altI

⫛ (does not intersect) alt/I

⊂ (strict subset) alt(

⊃ (strict superset) alt)

⊆ (subset or equal) alt _ (

⊇ (superset or equal) alt _ )

---

∗ (centred asterisk) alt*

÷ (division) altshift/

× (times) alt8

｜ (bar) alt|

‖ (double bar) alt||

∤ (not bar) alt/|

◁ (left triangle) alt<|

▷ (right triangle) alt|>

◇ (diamond) alt<>

∘ (circle) alt0

· (centred dot) alt.

⊗ (circled times) alt08

⊛ (circled asterisk) alt0*

⊖ (circled minus) alt0-

⊕ (circled plus) alt0+

⊘ (circled slash) alt0/

⊙ (circled dot) alt0.

---

≝ (defined equal) altshift=

≠ (not equal) alt/= or alt=/

≡ (equivalent) alt==

≈ (approx) alt~~

≤ (less than or equal) alt _ < or alt< _

≥ (greater than or equal) alt _ >

---

∴ (therefore) altT

∵ (because) altB

∞ (infinity) alt9

∇ (nabla) altV

² (squared) altshift2

³ (cubed) altshift3

√ (root) altv

---

I have used this set-up for several years now, and am very happy with it. It is particularly useful when composing mathematical emails, where LaTeX is not available. The only snag I have found is that in some programs, some keyboard shortcuts that use alt no longer work. To tackle this, I configured the keyboard shortcut cmdspace so that I can switch back to my default British layout whenever necessary.

2. Getting LaTeX to understand Unicode symbols

Note: you're probably better off using XeTeX if you want Unicode in your LaTeX source files. But let's suppose you want to stick with vanilla LaTeX for the time being.

I save the following in the file MathUnicode.sty and include the MathUnicode package in all my LaTeX files (that is, by putting \usepackage{MathUnicode} in the preamble).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Created by John Wickerson, 07 Jan 2010.
% Updated 28 Mar 2010.
% For use with the MathUnicode keyboard layout.

\RequirePackage[T1]{fontenc}
\RequirePackage[utf8x]{inputenc}
\RequirePackage{amssymb}
\RequirePackage{stmaryrd}

\DeclareUnicodeCharacter{183}{\cdot}
\DeclareUnicodeCharacter{915}{\ensuremath{\Gamma}}
\DeclareUnicodeCharacter{916}{\ensuremath{\Delta}}
\DeclareUnicodeCharacter{918}{\ensuremath{\Zeta}}
\DeclareUnicodeCharacter{920}{\ensuremath{\Theta}}
\DeclareUnicodeCharacter{923}{\ensuremath{\Lambda}}
\DeclareUnicodeCharacter{926}{\ensuremath{\Xi}}
\DeclareUnicodeCharacter{928}{\ensuremath{\Pi}}
\DeclareUnicodeCharacter{931}{\ensuremath{\Sigma}}
\DeclareUnicodeCharacter{933}{\ensuremath{\Upsilon}}
\DeclareUnicodeCharacter{934}{\ensuremath{\Phi}}
\DeclareUnicodeCharacter{935}{\ensuremath{\Chi}}
\DeclareUnicodeCharacter{936}{\ensuremath{\Psi}}
\DeclareUnicodeCharacter{937}{\ensuremath{\Omega}}
\DeclareUnicodeCharacter{945}{\ensuremath{\alpha}}
\DeclareUnicodeCharacter{946}{\ensuremath{\beta}}
\DeclareUnicodeCharacter{947}{\ensuremath{\gamma}}
\DeclareUnicodeCharacter{948}{\ensuremath{\delta}}
\DeclareUnicodeCharacter{949}{\ensuremath{\epsilon}}
\DeclareUnicodeCharacter{950}{\ensuremath{\zeta}}
\DeclareUnicodeCharacter{951}{\ensuremath{\eta}}
\DeclareUnicodeCharacter{952}{\ensuremath{\theta}}
\DeclareUnicodeCharacter{953}{\ensuremath{\iota}}
\DeclareUnicodeCharacter{954}{\ensuremath{\kappa}}
\DeclareUnicodeCharacter{955}{\ensuremath{\lambda}}
\DeclareUnicodeCharacter{956}{\ensuremath{\mu}}
\DeclareUnicodeCharacter{957}{\ensuremath{\nu}}
\DeclareUnicodeCharacter{958}{\ensuremath{\xi}}
\DeclareUnicodeCharacter{959}{\ensuremath{\omicron}}
\DeclareUnicodeCharacter{960}{\ensuremath{\pi}}
\DeclareUnicodeCharacter{961}{\ensuremath{\rho}}
\DeclareUnicodeCharacter{963}{\ensuremath{\sigma}}
\DeclareUnicodeCharacter{964}{\ensuremath{\tau}}
\DeclareUnicodeCharacter{965}{\ensuremath{\upsilon}}
\DeclareUnicodeCharacter{966}{\ensuremath{\phi}}
\DeclareUnicodeCharacter{967}{\ensuremath{\chi}}
\DeclareUnicodeCharacter{968}{\ensuremath{\psi}}
\DeclareUnicodeCharacter{969}{\ensuremath{\omega}}
\DeclareUnicodeCharacter{8214}{\parallel}
\DeclareUnicodeCharacter{8450}{\mathbb{C}}
\DeclareUnicodeCharacter{8470}{\mathbb{N}}
\DeclareUnicodeCharacter{8474}{\mathbb{Q}}
\DeclareUnicodeCharacter{8477}{\mathbb{R}}
\DeclareUnicodeCharacter{8484}{\mathbb{Z}}
\DeclareUnicodeCharacter{8614}{\mathbin{\mapsto}}
\DeclareUnicodeCharacter{8656}{\Leftarrow}
\DeclareUnicodeCharacter{8657}{\Uparrow}
\DeclareUnicodeCharacter{8658}{\Rightarrow}
\DeclareUnicodeCharacter{8659}{\Downarrow}
\DeclareUnicodeCharacter{8669}{\rightsquigarrow}
\newcommand{\eqdef}{\stackrel{{\scriptsize\rm def}}{=}}
\DeclareUnicodeCharacter{8797}{\eqdef}
\DeclareUnicodeCharacter{8870}{\vdash}
\DeclareUnicodeCharacter{8873}{\Vdash}
\DeclareUnicodeCharacter{8871}{\models}
\DeclareUnicodeCharacter{9121}{\lceil}
\DeclareUnicodeCharacter{9123}{\lfloor}
\DeclareUnicodeCharacter{9124}{\rceil}
\DeclareUnicodeCharacter{9126}{\rfloor}
\DeclareUnicodeCharacter{9655}{\triangleright}
\DeclareUnicodeCharacter{9665}{\triangleleft}
\DeclareUnicodeCharacter{9671}{\diamond}
\DeclareUnicodeCharacter{9675}{\circ}
\DeclareUnicodeCharacter{10178}{\bot}
\DeclareUnicodeCharacter{10214}{\llbracket} % needs stmaryrd
\DeclareUnicodeCharacter{10215}{\rrbracket} % needs stmaryrd
\DeclareUnicodeCharacter{10229}{\longleftarrow}
\DeclareUnicodeCharacter{10230}{\longrightarrow}
\DeclareUnicodeCharacter{10231}{\longleftrightarrow}
\DeclareUnicodeCharacter{10232}{\Longleftarrow}
\DeclareUnicodeCharacter{10233}{\Longrightarrow}
\DeclareUnicodeCharacter{10234}{\Longleftrightarrow}
\DeclareUnicodeCharacter{10236}{\longmapsto}
\DeclareUnicodeCharacter{10238}{\Longmapsto} % needs stmaryrd
\DeclareUnicodeCharacter{10503}{\Mapsto}    % needs stmaryrd
\DeclareUnicodeCharacter{10971}{\mathrel{\not\hspace{-0.2em}\cap}}
\DeclareUnicodeCharacter{65294}{\ldotp}
\DeclareUnicodeCharacter{65372}{\mid}