[Tugindia] Bold inside math environment

[Naren Bharatwaj]

Could somebody help me out with this. I need to get some text in bold inside
math mode. For eg.

$P_{LMP}$

It is not an equation or a symbol and need not be in Italics. It just needs
to be bold. The problem I am facing is that to get "LMP" as a subscript, I
need to give it inside a math environment. I tried mathbf but it didn't
workout for me. Thanks in advance.

Regards,

Naren Bharatwaj. V