from matplotlib import pyplot as plt
import matplotlib as mpl
mpl.rc('text', usetex=True)
mpl.rc('text.latex', preamble = ','.join(r'''
\usepackage{txfonts}
\usepackage{lmodern}
'''.split()))
%matplotlib inline
fig,ax = plt.subplots(1,1,figsize=(4,4))
ax.plot((1,5),(1,5))
ax.set_title('upright mu symbol: $\muup$ \n italic mu: $\mu$')
Text(0.5,1,'upright mu symbol: $\\muup$ \n italic mu: $\\mu$')