Pmb

Poor-man's bold: draw the same operand twice, with the second copy offset by 0.02 em horizontally and 0.01 em downward. Advance, baseline, and logical height remain unchanged; the extra ink is retained as overhang.

Property	Default	Meaning
children	Empty	Overprinted operand.
klass / left / right	"mord"	Atom classes of the completed box.

Strings parse as TeX. The direct element is an ordinary atom unless klass overrides it. Parsed \pmb{…} preserves a binary or relation argument's classification. For actual bold font outlines, prefer \mathbf, \boldsymbol, or the face controls on TextMode.