I am using \mathbf{} for include bold symbols in my equation. It works fine with all symbols with the exception of \iota. I tried to use equation environment and to exclude subindex. The following is my writing:
\begin{align}
\mathbf{Y}=\rho \mathbf{WY}+\alpha \mathbf{\iota}_{N}+\mathbf{X\beta}+\mathbf{WX\theta}+\mathbf{u},\label{eqgeneral1}\\
\mathbf{u}=\lambda\mathbf{Wu}+\mathbf{\varepsilon} \label{eqgeneral2}
\end{align}
I obtain this:
I want this:
¿How can I solve this?


\mathbf{}and the standard LaTeX font applies to Roman letters only, not Greek letters, not symbols like + - =, nothing like that. Try: https://tex.stackexchange.com/questions/595/how-can-i-get-bold-math-symbols – Au101 Aug 30 '18 at 19:29\bmor\boldsymbol. – Bernard Aug 30 '18 at 19:44unicode-mathinstead of legacy font packages. Any Unicode math font is going to come with bold math symbols. You can use them with\symbf{\iota}or\mathbf{\iota}. It’s also possible to do more complex things, such as using a different font for your Greek alphabet. – Davislor Aug 31 '18 at 02:30isomathpackage, which supports a large number of Greek math alphabets. You can also use a LGR-encoded legacy Greek font withmathastext. – Davislor Aug 31 '18 at 02:31