Extensions de repr\'esentations de de Rham et vecteurs localement alg\'ebriques

Let $\mathrm{\Pi }$ be an irreducible unitary completion of a locally algebraic ${\rm GL}_2(\qp)$-representation\mathrm{.}Wedescribethosefirst-orderdeformationsof$\Pi$ which are themselves completions of a locally algebraic representation. This answers a question of Paskunas and has direct applications to the Breuil-M'ezard conjecture.