我想在图例中写x下标0，但我无法做到这一点
legend("topright",c(paste("pinnacle / mean = ", m, ",x[0]= change point / mean = 0.5"), paste("pinnacle / mean = ", m, ", x[0]=change point / mean = 1"),paste("pinnacle / mean = ", m, ", x[0]=change point / mean = 2"),paste("pinnacle / mean = ", m, ", x[0]=change point / mean = 3")), lty=(1:4))