When I input Backsub in Mathematica 10.2 and press Ctrl+K after, I couldn't get Backsubstitution. My OS is Windows 8 32-bit.


I found following symbol doesn't auto-complete also.





  • 1
    $\begingroup$ I can confirm that Backsubstitution is not being offered as a hint on my system either (on 10.2 on Win7-64bit). I would suggest that you report that to WRI. As to the Ctrl+K part, that doesn't actually autocomplete a partial match on my system for other keywords either. $\endgroup$
    – MarcoB
    Commented Jul 23, 2015 at 2:34
  • $\begingroup$ Would someone kindly test my answer below and tell me if it fails? If it does can you figure out why? Has the file format or location change? $\endgroup$
    – Mr.Wizard
    Commented Apr 14, 2017 at 9:29
  • 2
    $\begingroup$ @Mr.Wizard Location is different, but the file format is the same. It looks like an issue in V11. If one updates Reduce.m in FileNameJoin[{$InstallationDirectory, "SystemFiles", "Components", "AutoCompletionData", "Main", "OptionValues"}] one doesn't get offered Backsubstitution after one writes Bac, but if one fully spells out Backsubstitution one finally gets True / False selection box. $\endgroup$
    – Ray Shadow
    Commented Apr 15, 2017 at 9:01

1 Answer 1

  1. Please refer to: Prompt a set of possible options

  2. Make a backup, then open Reduce.m

  3. Edit it to read:

    {Cubics -> {"True", "False"}, GeneratedParameters -> {}, 
     Quartics -> {"True", "False"}, Backsubstitution -> {"True", "False"}}
  4. Save the file

  5. Restart Mathematica

  6. Enjoy the result

enter image description here

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  • $\begingroup$ Thank you, but it doesn't worked as exepted on my PC. $\endgroup$
    – matrix42
    Commented Jul 27, 2015 at 11:43
  • $\begingroup$ I am running version 10.1.0 so I cannot rule out a change in 10.2.0 but it surprises me. I take it the appropriate file did exist on your system, and its contents were as above except for the missing , Backsubstitution -> {"True", "False"} part? $\endgroup$
    – Mr.Wizard
    Commented Jul 27, 2015 at 13:21

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