• Galois cohomology
• splitting families
• torsors
• Yoneda extensions group

The aim of this thesis is the construction of splitting families in Galois cohomology, following the homonymous article of Demarche and Florence. This is done by using two tools, one algebraic and one geometric. The algebraic one is given by the Yoneda extensions group, which has been introduced to extend the Ext functor to all the abelian categories. The geometric one is given by torsors. By using the language of torsors, we can see the first Galois cohomology set from a geometric point of view.