bm – Ac­cess bold sym­bols in maths mode

The bm pack­age de­fines a com­mand \bm which makes its ar­gu­ment bold. The ar­gu­ment may be any maths ob­ject from a sin­gle sym­bol to an ex­pres­sion. This is closely re­lated to the spec­i­fi­ca­tion of the \boldsym­bol com­mand in AMS-LaTeX, but \bm is rather more care­ful in the way it does things.
The pack­age is part of the tools bun­dle in the LaTeX re­quired dis­tri­bu­tion.