Laplace Transform drops unary minus

[Quiigi]

The file yacas/transforms.rep/code.ys starts like this:

10 # LaplaceTransform(_var1,_var2, _expr )      <-- LapTran(var1,var2,expr);

// Linearity properties 
10 # LapTran(_var1,_var2,_x + _y)               <-- LapTran(var1,var2,x) + LapTran(var1,var2,y);
10 # LapTran(_var1,_var2,_x - _y)               <-- LapTran(var1,var2,x) - LapTran(var1,var2,y);
10 # LapTran(_var1,_var2,    - _y)              <-- LapTran(var1,var2,y);

I believe that last rule, on line 6, is incorrect. To correctly express linearity, it should preserve the sign, i.e.,

10 # LapTran(_var1,_var2,    - _y)              <-- - LapTran(var1,var2,y);

Likely that issue exists upstream in yacas itself, and is not specific to this R interface.

[mikldk]

@grzegorzmazur Can you help here? Should this issue be created at https://github.com/grzegorzmazur/yacas/issues instead?

[grzegorzmazur]

Yes, please.

[mikldk]

@Quiigi Can I please ask you to open this issue in the yacas repo ^^?

[grzegorzmazur]

OK, fixed (but for now only in upstream yacas). Thank you for finding and reporting the issue :)