6.22 Issue

Hi everyone,

I’m having an issue with problem 6.22. I can prove ¬(b=c) in step 11 by using ¬Intro and citing 3-10, but for some reason Fitch won’t give me the final check for ¬(b=c) in my goal box. Meaning, every step from 1-11 gets the green check but for some reason the proof as a whole does not. Anyone running up against this issue or have an idea about what I’m doing wrong?

3 thoughts on “6.22 Issue

  1. Mariana Zieve-Cohen

    Hey Sara,

    I am not sure if this will be helpful as I am replying so late so I apologize about that but I was having a similar issue a few weeks back. I believe that in order to receive the green check mark in the goal box you have to be using the file that Fitch already created. In other words if a Fitch file already exists for exercise 6.22 you must use that file. It will not work if you create a new one. Again, sorry for the delayed response but I hope this can help you or others in the future!

  2. Kareem Khalifa

    Hi All, A lot of folks have had similar kinds of problems. Often, it’s a weird software issue. One way to check this is to see if doing a “dry run” on Submit returns a positive evaluation on the problem. I think some students have reported that creating a new Fitch file from scratch also solves some of these problems. If others can share fixes for situation in which they are confident that their solution to a problem is correct, but the software indicates otherwise, that would be very useful.

  3. Tobie Gumener

    Hey Sara,

    That’s very weird. Your number of steps is correct, your rule for step 11 is correct, and so are your citations. The only thing I can think of right now is perhaps you did not make correct indentations (i.e. you might have started/ended subproofs at the wrong moments). To give you my outline, my 3rd step is the start of a subproof (one indentation), and under this I have two, seperated sub-subproofs (steps 4-6, and steps 7-9, both at two indentations). The 10th step is concluding my initial subproof (back to one indentation), and step 11 is written as part of the normal proof (no indentation). I hope this can help you out.


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