Example of a Tuple of Identical Elements (β, β, ..., β)

In a machine learning context, you need to create an initial weight vector of length 'n'. A specific initialization strategy requires that every single element in this vector must have the exact same starting value of 0.5. Which of the following expressions correctly and most concisely represents this specific vector?

A data scientist is creating a feature vector of length 'd' for a machine learning model. A specific preprocessing step requires that every element in this vector be set to the same numerical constant, represented by the Greek letter λ (lambda). The standard mathematical notation for this vector would be (λ, ..., ___).