# MathematicalSystems.jl with input constraint only

**URL:** <https://discourse.julialang.org/t/mathematicalsystems-jl-with-input-constraint-only/95123>\
**Category:** Modelling & Simulations\
**Created:** [February 24, 2023, 11:12am UTC](https://discourse.julialang.org/t/mathematicalsystems-jl-with-input-constraint-only/95123 "2023-02-24T11:12:58Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![bienpierre](https://avatars.discourse-cdn.com/v4/letter/b/8c91f0/32.png) [@bienpierre](https://discourse.julialang.org/u/bienpierre)\
**Post date:** [February 24, 2023, 11:12am UTC](https://discourse.julialang.org/t/mathematicalsystems-jl-with-input-constraint-only/95123/1 "2023-02-24T11:12:58Z")

</div>

Dear all,

I would like to know if there is a mathematical system structure with only input constraints, for instance:

```julia
julia> using LazySets
julia> using MathematicalSystems
julia> A = [1 1; 0 0.9]
julia> B = [1; 0.5]
julia> U = Hyperrectangle(low=[-1], high=[1])
julia> system = @system x⁺ = A*x + B*u u∈U

```

It provides me an issue:

```julia
julia> system = @system x⁺ = A*x + B*u u∈U
ERROR: ArgumentError: the entry (:A, :B, :U) does not match a `MathematicalSystems.jl` structure
Stacktrace:
 [1] top-level scope
   @ REPL[6]:1

```

Is there a workaround?

Warmest regards