FCEnableTraditionalFormOutput[] sets the output format
of the current FrontEnd to TraditionalForm. The setting is
not persistent, such that it does not influence any subsequent
Mathematica FrontEnd sessions.
Overview, $FCTraditionalFormOutput, FCDisableTraditionalFormOutput.
FCDisableTraditionalFormOutput[]
FV[p, \[Mu]]\overline{p}^{\mu }
FCEnableTraditionalFormOutput[]
FV[p, \[Mu]]\overline{p}^{\mu }