Unified Model of k-Inflation, Dark Matter & Dark Energy
  We present a \textit{k}-essence model where a single scalar field is
responsible for the early expansion of the universe through the process of
\textit{k}-inflation and at appropriate subsequent stages acts both as dark
matter and dark energy. The Lagrangian contains a potential for the scalar
field as well as a non-canonical kinetic term, and is of the form $F(X)V(\phi)$
which has been widely used as a \textit{k}-essence Lagrangian. After the period
of inflation is over the model can be approximated as purely kinetic
\textit{k}-essence, generating dark matter and dark energy at late times. We
show how observational results are used to put constraints on the parameters of
this model.
