For your equations to make sense, you have to specify a couple of things:

• Specify how $\vec{k}$ is defined. For instance $$ \vec{k} = k^\mu\gamma_\mu $$
• Specify how $k^\mu$ transform under Lorentz transformation.
• Specify whether parameters $k^\mu$ are fundamental constants. And if they are not Lorentz scalar, how do you justify that fundamental constants are reference frame dependent?

For your equation to make sense, you have to specify a couple of things:

• Specify how $\vec{k}$ is defined. For instance $$ \vec{k} = k^\mu\gamma_\mu $$
• Specify how $k^\mu$ transform under Lorentz transformation.
• Specify whether parameters $k^\mu$ are fundamental constants. And if they are not Lorentz scalar, how do you justify that fundamental constants are reference frame dependent?

You have to do a couple of things:

• Specify how $\vec{k}$ is defined. For instance $$ \vec{k} = k^\mu\gamma_\mu $$
• Specify how $k^\mu$ transform under Lorentz transformation.
• Specify whether parameters $k^\mu$ are fundamental constants. And if they are not Lorentz scalar, how do you justify that fundamental constants are reference frame dependent?

For your equations to make sense, you have to specify a couple of things:

• Specify how $\vec{k}$ is defined. For instance $$ \vec{k} = k^\mu\gamma_\mu $$
• Specify how $k^\mu$ transform under Lorentz transformation.
• Specify whether parameters $k^\mu$ are fundamental constants. And if they are not Lorentz scalar, how do you justify that fundamental constants are reference frame dependent?