Cosmographic parameters in model-independent approaches
  Cosmographic approach, a Taylor expansion of the Hubble function, has been
used as a model-independent method to investigate the evolution of the universe
in the presence of cosmological data. Apart from possible technical problems
like the radius of convergence, there is an ongoing debates about the tensions
appear when one investigates some high redshift cosmological data. In this
work, we consider two common data sets namely SNIa (Pantheon sample) and the
Hubble data to investigate advantages and disadvantages of the cosmographic
approach. To do this, we obtain the evolution of cosmographic functions using
cosmographic method as well as two other well known model-independent
approaches namely, the Gaussian process and the Genetic algorithm. We also
assume $\Lambda$CDM model as concordance model to compare the results of
mentioned approaches. Our results indicate that the results of cosmography
comparing with the other approaches, are not exact enough. Considering the
Hubble data which is less certain, the results of $q_0$ and $j_0$ obtained in
cosmography, provides a tension at more than $3\sigma$ away from the best
result of $\Lambda$CDM. Assuming both of data samples in different approaches
we show that the cosmographic approach, because of providing some biased
results, is not the best approach for reconstruction of cosmographic functions,
especially at higher redshifts.
