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A dataset of instances and solutions (if they exist) for Post’s correspondence problem
These were given on page 757 of A New Kind of Science (Wolfram, 2002)
(2 columns, 19 rows)
Retrieve the default content:
| In[1]:= | ![ResourceData["Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"]](https://www.wolframcloud.com/obj/resourcesystem/images/53d/53db85ed-136f-47ca-a909-6977c6f4f027/701547500248b427.png) | 
| Out[1]= |  | 
Find the correspondences for the first example:
| In[2]:= | ![Normal[ResourceData[
   "Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"][[1, "Correspondences"]]]](https://www.wolframcloud.com/obj/resourcesystem/images/53d/53db85ed-136f-47ca-a909-6977c6f4f027/5952db79dac417e0.png) | 
| Out[2]= |  | 
Find the solution for the first example:
| In[3]:= | ![Normal@ResourceData[
   "Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"][[1, "Solution"]]](https://www.wolframcloud.com/obj/resourcesystem/images/53d/53db85ed-136f-47ca-a909-6977c6f4f027/60387fef8013887d.png) | 
| Out[3]= |  | 
Use the solution for the first problem:
| In[4]:= | ![Transpose[
  Normal@ResourceData[
     "Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"][[1, "Correspondences"]]][[All, Normal@ResourceData[
    "Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"][[1, "Solution"]]]]](https://www.wolframcloud.com/obj/resourcesystem/images/53d/53db85ed-136f-47ca-a909-6977c6f4f027/6648b97f553e52aa.png) | 
| Out[4]= |  | 
Confirm that the strings are the same:
| In[5]:= | ![StringJoin /@ Transpose[
   Normal@ResourceData[
      "Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"][[1, "Correspondences"]]][[All, Normal@ResourceData[
     "Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"][[1, "Solution"]]]]](https://www.wolframcloud.com/obj/resourcesystem/images/53d/53db85ed-136f-47ca-a909-6977c6f4f027/7247117ed445f67a.png) | 
| Out[5]= |  | 
| In[6]:= | ![StringJoin /@ Transpose[
   Normal@ResourceData[
      "Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"][[1, "Correspondences"]]][[All, Normal@ResourceData[
     "Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"][[1, "Solution"]]]]](https://www.wolframcloud.com/obj/resourcesystem/images/53d/53db85ed-136f-47ca-a909-6977c6f4f027/224f7283f07cc644.png) | 
| Out[6]= |  | 
Make a graphical version of the solution for the 10th problem:
| In[7]:= | ![ArrayPlot[
    {Flatten@Map[StringPartition[#, 1] &, #]},
    ColorRules -> {
      "a" -> Black,
      "b" -> White
      },
    ImageSize -> Large
    ] & /@ Transpose[
    Normal@ResourceData[
       "Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"][[10, "Correspondences"]]][[All, Normal@ResourceData[
      "Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"][[10, "Solution"]]]] // Column](https://www.wolframcloud.com/obj/resourcesystem/images/53d/53db85ed-136f-47ca-a909-6977c6f4f027/3798d9951c31376b.png) | 
| Out[7]= |  | 
Show each step of the solution for the 5th problem:
| In[8]:= | ![Row@*
   Map[
    ArrayPlot[
      List@StringPartition[#, 1],
      ColorRules -> {
        "a" -> Black,
        "b" -> White
        },
      ImageSize -> {Automatic, 15}
      ] &
    ] /@ Transpose[
    Normal@ResourceData[
       "Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"][[5, "Correspondences"]]][[All, Normal@ResourceData[
      "Solutions to Examples of Post\[CloseCurlyQuote]s Correspondence Problem"][[5, "Solution"]]]] // Column](https://www.wolframcloud.com/obj/resourcesystem/images/53d/53db85ed-136f-47ca-a909-6977c6f4f027/224f45df2ffac542.png) | 
| Out[8]= |  | 
| In[9]:= |  | 
Wolfram Research, "Solutions to Examples of Post’s Correspondence Problem" from the Wolfram Data Repository (2017) https://doi.org/10.24097/wolfram.68271.data