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 $E_0 \simeq 10^{19}$ eV recorded by ground-based and underground scintillation detectors with a threshold of $E_{\mu} \simeq 1.0 \times \sec\theta$ GeV at the Yakutsk array during the continuous observations from 1986 to 2016 have been analyzed using events with zenith angles $\theta \le 60^{\circ}$ functions have been compared to the predictions obtained with the QGSJet01 hadron interaction model by applying the CORSIKA code. The entire dataset indicates that cosmic rays consist predominantly of protons.