Constraining f(T) teleparallel gravity by Big Bang Nucleosynthesis
  We use BBN observational data on primordial abundance of ${}^4He$ to
constrain f(T) gravity. The three most studied viable $f(T)$ models, namely the
power law, the exponential and the square-root exponential are considered, and
the BBN bounds are adopted in order to extract constraints on their free
parameters. For the power-law model, we find that the constraints are in
agreement with those acquired using late-time cosmological data. For the
exponential and the square-root exponential models, we show that for realiable
regions of parameters space they always satisfy the BBN bounds. We conclude
that viable f(T) models can successfully satisfy the BBN constraints.
