# Negative scalar to tensor ratio

Recently I've read some papers on inflation and slow roll approximation. As we all know, inflation parameters are constrained by recent Bicep2/Keck and Planck data, which gives values of scalar-to-tensor ratio as well as spectral index of primordial curvature perturbations - i have simple or even naive question - since scalar to tensor ratio is constrained (for example 2014 data) as: $$r<0.10$$ does it mean that this ratio can be negative?