THE FAITHFULNESS OF AN EXTENSION OF LAWRENCE-KRAMMER-BIGELOW REPRESENTATION ON THE GROUP OF CONJUGATING AUTOMORPHISMS $C_n$ in the cases $n=3$ and $n=4$

Let $C_n$ be the group of conjugating automorphisms. V. Bardakov defined a representation $\rho$ of $C_n$, which is an extension of Lawrence-Krammer-Bigelow representation of the braid group $B_n$. Bardakov proved that the representation $\rho$ is unfaithful for $n \geq 5$. The cases $n=3,4$ remain open. M. N. Nasser and M. N. Abdulrahim made attempts towards the faithfulness of $\rho$ in the case $n=3$. In this work, we prove that $\rho$ is unfaithful in the both cases $n=3$ and $n=4$.