Kdtyjb

In my experience, there is no single best way. Therefore Table 327 on page 225 of the Comprehensive LaTeX Symbol List comes in really handy.

Visited March 8, 2019: Table 528 on page 225 of the Comprehensive LaTeX Symbol List comes in really handy.

With unicode-math you can use symbf{<characters>} which works for both Greek and Latin letters. (In versions of unicode-math older than 0.8 the symXXX macros didn't exist, but you could mathbf{<characters>} directly.)

Compile with xelatex or lualatex.

documentclass{article}

usepackage{unicode-math}

setmathfont{xits-math.otf}

begin{document}

( AaBb∇αβγ ) par

( symbf{AaBb∇αβγ} ) par

( symrm{AaBb∇αβγ} )

end{document}

Another possibility is boldmath, though I would prefer boldsymbol of amsmath as well. unboldmath switches back to the normal math font.

If you use the package bm you can do $bm{a}=bm{alpha}$ etc.

While bm and boldmath are some good options in LaTeX, modern packages for XeLaTex can give a lot more control over the fonts from the very beginning, without the need to use commands different from the standard mathbf that every one expects naively to work the first time one tries to write bold italic characters.

In XeLaTeX (part of TeXLive), the package fontspec gives a lot of freedom when dealing with fonts. If you want even more flexibility for mathematical input, you can try using the package unicode-math (that is built on fontspec). Nevertheless you will find the bm and boldsymbol traditional commands don't work. You can nonetheless specify how you want it to deal with your bold math symbols using an option while loading the unicode-math package. usepackage[bold-style=ISO]{unicode-math} will give the recommended italic bold math symbols for both greek and latin characters, while usepackage[bold-style=TeX]{unicode-math} will give upright latin characters. This is explained in the unicode-math documentation .

This minimal working example:

%run this with XeLaTeX!!

documentclass{article}

usepackage[bold-style=ISO]{unicode-math}

%usepackage[bold-style=TeX]{unicode-math}

setmainfont{XITS}

setmathfont{XITS Math}





begin{document}



This is common math $O(log n)+O(lambda,,epsilon)$



This is bold and italic $mathbf{O(log n)}+mathbf{O(lambda,,epsilon)}$ where it must :)

end{document}

gives

In order to have just one command for both bold text and bold math, one can use the solution suggested on LaTeX Community (/forum/viewtopic.php?t=10866&f=44#p42084, link not allowed). Editing this solution slightly in order to incorporate the bm package, one could use the following.

usepackage{bm}

newcommand*{B}[1]{ifmmodebm{#1}elsetextbf{#1}fi}

My solution (the one that I use) is the mathversion{bold} and mathversion{normal} commands.

This piece of code is not a MWE —however, it shows how to use them:

mathversion{bold}

section{Behavior of $f$ as a function of $lambda$}label{sec:1}

mathversion{normal}



And now, imagine that mathversion{bold}textbf{we want to put some

text in bold, and that this text contains some inline equation such as

$sum_{j=0}^{t-1}{{p_mathrm{y}(lambda=2)}^j}$.}mathversion{normal}

Hope it helps.

Another option:

documentclass{article}

newcommand{boldm}[1] {mathversion{bold}#1mathversion{normal}}

begin{document}



There is a normal symbol, $p_1$. Now, a bold symbol: {boldm $p_2$}. It works!



end{document}

Output:

Use the command boldsymbol{YOUR_SYMBOL}

You can use physics package and write any math symbol in boldface by using command vb{} inside mathmode, e.g. $vb{Psi}$ will yield Ψ.

The unicode-math package supports several commands for bold symbols beyond what have been mentioned in previous answers, including mathbf, symbf, symbfup, symbfit, boldmath and mathversion{bold}. If you load amsmath or mathtools first, it will also redefine boldsymbol.

If you load a math font that has a bold version, unicode-math will load it as version=bold. The ones that ship with TeX Live 2018 are Khaled Hosny’s XITS Math Bold and Libertinus Math Bold, and there is a Minion Math Bold as well. It is also possible to load any math font with setmathfont[version=bold].

Here’s a brief MWE that uses boldmath, symbf and boldsymbol. Note that mathbf will use the bold weight of the main text font, symbf will use the mathematical bold letters and numerals defined in the Unicode Mathematical Alphenumeric Characters block, and boldmath, mathversion{bold} and boldsymbol will use the bold math font (if there is one).

documentclass[varwidth = 10cm, preview]{standalone}

usepackage{mathtools}

usepackage[math-style=ISO]{unicode-math}

usepackage{microtype}



defaultfontfeatures{ Scale = MatchUppercase }

setmainfont{Libertinus Serif}[Scale = 1.0, Ligatures = Common]

setsansfont{Libertinus Sans}

setmonofont{Libertinus Mono}

setmathfont{Libertinus Math}



begin{document}

section*{boldmath Reasoning from (symbf{A} vee symbf{B})}



If we have (symbf{A} vee symbf{B}) and (symbf{A}), disjunctive syllogism

(classically known as textbf{textit{modus ponendo tollens}}, and also known

as textbf{disjunction elimination} or {boldmath (vee E)}) is the rule

that lets us conclude (boldsymboltherefore symbf{B}).



end{document}

There are several ways to tweak this behavior. By default, mathbf renders bold capital letters upright and bold lowercase letters italic, but [math-style=ISO] makes italic the default for everything, including regular-weight uppercase Greek. You can change only the behavior of bold uppercase letters with bold-style=ISO] or [bold-style=upright]. You can also specify symbfup for bold upright or symbfit for bold italic.

Observe how ugly pmb is in the following example, compared to bm:

documentclass{article}

usepackage{amsmath, bm}

begin{document}

$$Psi_n pmb{Psi_n} bm{Psi_n} boldsymbol{Psi_n} Psi_n$$

end{document}