The idea of this issue is to add possibilities of declaration of time, state, control and variable.

For instance, this current declaration

@def begin
    tf ∈ R, variable
    t ∈ [0, tf], time
    x = (q, v) ∈ R², state
    u ∈ R, control
    tf ≥ 0 
    v(t) ≤ 1
    -1 ≤ u(t) ≤ 1
end

must be equivalent to

@def begin
    tf ∈ R₊, variable
    t ∈ [0, tf], time
    x = (q, v) ∈ (-∞, 1] × R, state
    u ∈ [-1, 1], control
end

In the comments below, you will find:

• Preliminaries: how the code works.
• Current possibilities: how to declare for the moment.
• Todo: the new possibilities.