search for: friction_linear_chain_perpendicular

Dear All, I am sure this is a one-liner, but I cannot find the R command to generate the LaTex symbols \perp and \parallel. Consider for instance the figure (one can use any kind of data for the plot) pdf("friction_linear_chain_perpendicular.pdf") par( mar = c(4.5,5, 2, 1) + 0.1) plot(data[ ,1], data[ ,4],col="blue",lwd=1.5,lty=1,pch=5,ylab=expression(""*beta[n]^{perpendicular}/beta[1]*""), xlab=expression(""*n*"") ,cex.axis=1.4,cex.lab=1.6) lines(x,beta_perp(as.list(coef(nl...