Bug in symbolic integration?

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Hendrik Suess

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Jun 15, 2021, 11:31:09 AMJun 15
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The following two functions

f(u)=-u/2+min_symbolic(0,u) + min_symbolic(u,2*u) and g(u)=-u/2+min_symbolic(u, 3*u)

are mathematically equivalent, but the following symbolic integrals give different results.

<code>

F(x)=integral(f(u)*u*exp(x*u),u,-1,1)
FF(y)=F(y)

G(x)=integral(g(u)*u*exp(x*u),u,-1,1)
GG(y)=G(y)

</code>

Now (FF-GG)(y).simplify_full() should give 0, but I am getting 4/y^3 instead.

This behaviour changed at some point in the past (breaking existing code). This issue occurs with Sage 9.3 (running in CoCalc with Software Environment Ubuntu 20.4). With Sage 8.3 (running in CoCalc with SE Ubuntu 18.04 @ 2018-08-27) the issue doesn't occur.


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