In the small program below, I don’t understand why label = r"$tilde{Q}$") runs well and label = r"$Large{Q}$") doesn’t run:

%matplotlib inline
import matplotlib.pyplot as plt

x = np.linspace(-3, +3, 100)
y = x**2

fig, ax = plt.subplots(figsize=(4, 2))
ax.plot(x, y,  label = r"$tilde{Q}$")
#ax.plot(x, y,  label = r"$Large{Q}$")
ax.legend(loc='best')
plt.show()

The error generated by label = r"$Large{Q}$" is incredibly verbose and I couldn’t find a simple explanation.

Any suggestion appreciated as to apply Large to a single letter in a label.