how to make DSolve not generate Assumptions in the solution?

Question

Sometimes Mathematica generates solutions to a PDE which are hard to read, since it attaches assumptions to the result. If a user knows these assumptions are obvious physically, they might want to avoid having them included in the output so that it is easier to read.

I do not know how to tell Mathematica to avoid showing these assumptions. The option GenerateConditions->False does not work here, since this is a call to DSolve which does not accept this option. But DSolve internally uses Integrate

Is there other ways to do this? Here is a MWE

Example 1

Remove[L0];
ClearAll[u,t,k,x,f];
pde=D[u[x,t],t]==k D[u[x,t],{x,2}];
bc={Derivative[1,0][u][0,t]==0,Derivative[1,0][u][L0,t]==0}
ic=u[x,0]==f[x];
sol=DSolve[{pde,bc,ic},u[x,t],{x,t}];
sol=sol/.{K[1]->n,K[2]->x}

The solution is correct. But I'd like to see it as

I do not know how to pass GenerateConditions->False to Integrate which is internally used by DSolve.

Btw, Maple generates the same answer, without those assumptions by default, which makes it little easier to read

restart;
L:='L'; u:='u'; t:='t'; x:='x';
interface(showassumed=0);
assume(L>0);
pde:=diff(u(x,t),t)=k*diff(u(x,t),x$2);
bc:=D[1](u)(0,t)=0,D[1](u)(L,t)=0:
ic:=u(x,0)=f(x):
sol:=pdsolve([pde,bc,ic],u(x,t)):
sol:=subs(_Z2=n,sol);

Example 2

It also depends on the PDE and the boundary conditions. For example, in this one, Mathematica generates strange Assumptions->True in the result, which I do not understand, and did not include assumptions on time or length or k as above. But the PDE solution is correct

Remove[L0];
ClearAll[u,t,k,x];
pde=D[u[x,t],t]==k D[u[x,t],{x,2}];
bc={u[0,t]==0,u[L0,t]==0};
ic=u[x,0]==f[x];
sol=DSolve[{pde,bc,ic},u[x,t],{x,t}];
sol=sol/.K[1]->n

In summary, I'd just like an option to disable display of Assumptions in result if possible.

I convert these results to Latex, and with assumptions there, the output is hard to read.

Using version 11.3 on windows.

Answer 1

How about modifying $PrePrint?:

(* Solution 1 *)
$PrePrint = (# /. HoldPattern@Integrate[a__, (_ -> _) ..] :> Integrate[a]) &;
(* Solution 2 *)
$PrePrint = (# /. HoldPattern@Integrate[a__, OptionsPattern[]] :> Integrate[a]) &;

Notice we've only changed the display, sol and Out[…] are still expressions involving Assumptions.

Answer 2

I hate to state the obvious, but does the following do what you want?

% /. Integrate[x___, Assumptions -> _, y___] :> Integrate[x, y]

Answer 3

If you just want to improve the TeXForm output, you could modify the TraditionalForm Integrate formatting definition:

Unprotect[Integrate];
Integrate /: MakeBoxes[
    Integrate[a__, OptionsPattern[]],
    TraditionalForm
] /;! TrueQ@$IntFlag := Block[{$Foo=True},
    MakeBoxes[Integrate[a],TraditionalForm]
]
Protect[Integrate];

Then:

Integrate[f[x]Sin[x],{x,0,L0},Assumptions->True] //TeXForm

$\int_0^{\operatorname{L0}} f(x) \sin (x) \, dx$