Muons in eass with $E_0=10^{19}$ ev according to data of the Yakutsk array

Lateral distribution functions of particles in extensive air showers with the energy $E_0\approx 10^{19}$ eV recorded by ground-based and underground scintillation detectors with a threshold of ${E}_{\mu } \approx 1.0 \times \text{sec}\, \theta $ GeV at the Yakutsk array during the continuous observations from 1986 to 2016 have been analyzed using events with zenith angles $\theta\leqslant60^\circ$. Experimental functions have been compared to the predictions obtained with the QGSJet-01-d hadron interaction model by applying the CORSIKA code. The entire dataset indicates that cosmic rays consist predominantly of protons.