0
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I evaluated

Refine[
  Conjugate[
    (-4 I kp^3 v^3 - 4 γ21 γ31 γ41 + 4 kp^2 v^2 (γ21 + γ31 + γ41 - 3 I δp))
      // Expand],
  (γ21 | γ31 | γ41 | kp | δp | v) ∈ Reals] // FullSimplify

and got

(* 4 (-γ21 γ31 γ41 + kp^2 v^2 (γ21 + γ31 + γ41) + 
   I Conjugate[kp]^2 Conjugate[v]^2 (Conjugate[kp v] + 3 Conjugate[δp])) *)  

How can I remove Conjugate from my result?

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  • $\begingroup$ FullSimplify[ Refine[Conjugate[(-4 I kp^3 v^3 - 4 \[Gamma]21 \[Gamma]31 \[Gamma]41 + 4 kp^2 v^2 (\[Gamma]21 + \[Gamma]31 + \[Gamma]41 - 3 I \[Delta]p)) // Expand]], (\[Gamma]21 | \[Gamma]31 | \[Gamma]41 | kp | \[Delta]p | v) \[Element] Reals] $\endgroup$ – ciao Aug 27 '15 at 23:33
  • $\begingroup$ Since I had to copy @ciao's code above and paste it into a notebook to notice the difference, I'll just write it out explicitly: ciao is suggesting that the right placement for those domain assumptions is as an option to FullSimplify, and not within Refine (which works perfectly). This Q&A exchange must have won some prize for terseness ;-) $\endgroup$ – MarcoB Aug 28 '15 at 0:28
  • 1
    $\begingroup$ There is always /. Conjugate -> Identity. Use at your own risk. $\endgroup$ – wxffles Aug 28 '15 at 0:33
  • $\begingroup$ Actually, this is what ComplexExpand is for: Conjugate[(-4 I kp^3 v^3-4 \[Gamma]21 \[Gamma]31 \[Gamma]41+4 kp^2 v^2 (\[Gamma]21+\[Gamma]31+\[Gamma]41-3 I \[Delta]p))//Expand]//ComplexExpand//FullSimplify $\endgroup$ – Jens Aug 28 '15 at 1:05
  • $\begingroup$ FullSimplify[Conjugate[-4 I kp^3 v^3 - 4 γ21 γ31 γ41 + 4 kp^2 v^2 (γ21 + γ31 + γ41 - 3 I δp)], (γ21 | γ31 | γ41 | kp | δp | v) ∈ Reals] also works well in this case, and does not require Refine or Expand. $\endgroup$ – bbgodfrey Aug 28 '15 at 1:08