If $(R,m)$ is a local Cohen-Macaulay ring, it is well-known that each system of parameters is an $R$-sequence.
Is any $R$-sequence (in a Cohen-Macaulay ring) a system of parameters?
I am aware of the fact that in a local ring any $R$-sequence is "part of" some system of parameter for $R$.
Thanks for answering!
No, it's not! A regular sequence can have less terms than $\dim R$.
However, if you ask if any maximal $R$-sequence is a sop in a local CM ring, then the answer is yes since $\operatorname{depth}R=\dim R$.