Dear All, this week and the last week I have spent some time in class discussing several exercises that provide a context-free language and ask you to design a context-free grammar that generates that language.
I am seeking now volunteers who can post some of the exercises that we have solved, so that students who have not been able to be at the lectures can still access that material.
Thank you very much in advance for your help with this!
Nobody has followed up with this thread ...
If you have some time this weekend please write down at least one of the exercises that have been done in class about CFGs. In this way we should be able to have a complete coverage of those activities.
Can you upload all the exercise from the last friday and the 31/10?
The grammars by both Gianmarco and Matteo are correct, I do not see any mistake.
Only comment: I do not understand the tree in the post by Matteo, that does not look like a valid parse tree for the grammar.
Dear professor,
You are absolutely correct, I am sorry for the mistake. I don't know why the picture was cropped.
In my notes I wanted to stress the fact that a language can be either expressed with a tree, so I came up with the parse tree that shows the derivation of the string aaabbb. The complete tree is a parse tree since I created the arcs from S to a and b and all the leaves are terminal symbols right?
Thanks a lot for your correction.
Ok Matteo, but your tree does not look right ... The node labeled S at the 2nd level should have three children according to the rule. Also, the symbols a and b at the second level should not have any child node.