Convergence conditions for integrals using holonomic functions

[certik]

Per #11319, even if we could solve it using holonomic functions, another advantage of the MeijerG integrator is that it returns convergence conditions. Here is an example:

In [89]: LaplaceTransform((exp(2*t) - 1)*exp(-b - t)*Heaviside(t)/2, t, s).rewrite(Integral).doit()
Out[89]: 
⎧               -b          -b                                                
⎪              ℯ           ℯ                                                 π
⎪         - ───────── - ──────────           for │periodic_argument(s, ∞)│ ≤ ─
⎪           2⋅(s + 1)   2⋅(-s + 1)                                           2
⎪                                                                             
⎪∞                                                                            
⎨⌠                                                                            
⎪⎮ ⎛ 2⋅t    ⎞  -s⋅t  -b - t                                                   
⎪⎮ ⎝ℯ    - 1⎠⋅ℯ    ⋅ℯ      ⋅Heaviside(t)                                      
⎪⎮ ───────────────────────────────────── dt                                   
⎪⎮                   2                                                        
⎪⌡                                                                            
⎩0                                                                            


                                                                            π 
 ∧ cos(│periodic_argument(s, ∞)│)⋅│s│ - 1 > 0 ∧ │periodic_argument(s, ∞)│ < ─ 
                                                                            2 





                     otherwise                                                





  1    
∧ ─ ≠ 1
  s    

It would be nice to know if we can get similar conditions using holonomic functions.

[certik]

I think the convergence conditions only arise if there are more than one variable. So we can tackle this issue after resolving #11323.