Ghideon

Generating combinations is not so hard. The problem is that there are so many combinations to generate. For the approach you have provided the wait will be very long.

It looks very similar to this thread: https://www.scienceforums.net/topic/123025-python-tree-program-multiple-children-module-error/?tab=comments#comment-1152593 have you tried that?

True, the statement seems ok (roots of quadratic equation)

Thanks, I'll check that later. Here is another one: Is that correct? It seems to imply that if 2>1 then 2<-1 which is not true.

This sounds like a different* approach than the random sentence generation in OP; encoding or embedding a large amount of specific knowledge before running any searches? Here is a paper about Deep Learning for Symbolic Mathematics: https://arxiv.org/abs/1912.01412 Here is an article commenting on the paper: https://www.quantamagazine.org/symbolic-mathematics-finally-yields-to-neural-networks-20200520/ Maybe the above is a simple version of what you are trying to achieve? *) I may have misunderstood something, could simply be a language issue.

Question: do you assume |a1| >=| a2| and |b1| >= |b2|? From your attached paper: Without |a1| >=| a2| and |b1| >= |b2| the square roots may be imaginary. Is that intended? From your attached paper:

Thanks for your reply. I'll wait until you provide some way you attempt to separate the valid data from the huge amount of invalid data. Also note that you keep repeating the same simple examples. An analogy with your rectangle: Assume the program gives "The area of a rectangle with sides 4 meters long is the sum of the length of its sides." 4+4+4+4 gives you 16 which happens to match the numerical value of the area. If we knew enough about area calculation to spot the issue then we had no need for the program? For a more contemporary example, the output could be something like "convolutional neural networks generally provide better results for image recognition than an architecture based on a recurrent neural network". it would be one of millions of similar statements.

You told me to wait: It seems though as my 1st question was answered. What we have looks pretty obvious; scientific papers written in the near future will most likely contain a combination of existing words (together with numbers and mathematical symbols). Even for some novel concept existing words and mathematics could be used to define the new concepts. My 2nd and 3rd question seems to be unanswered.

Some feedback for your idea: 1: Your example requires that the word "area" existed before anyone came up with the idea how to calculate area? Why would that be so, and why would it be so in general for new discoveries? 2: If we assume 1000 words (a small subset of English) and that a sentence of 10 words is sufficient to describe a novel discovery (I guess that is not nearly enough) then you have 2.6E+23 (263409560461970212832400) sentences* to choose from. Sorting out the interesting ones would require quite some effort? 3: Let's try the words in your first reply: Here are three examples using words from your sentence: I understand you very well. You don't understand very well. You don't understand. What algorithm should a computer (or human) use to select the sentence that "makes sense" unless it is already obvious? (I note that OP has hit the max 5 posts for first day.) Side note: Using a more advanced model for generating sentences can get interesting results. The Generative Pre-trained Transformer 3 (GPT-3) is capable of generating human-like text. But I would not expect it to autogenerate papers containing novel scientific discoveries. https://en.wikipedia.org/wiki/GPT-3 *) Algorithms could be used to not generate clearly invalid sentences, the example is just an illustration of the number of combinations.

Because they have syntax errors. Trailing back slash is not allowed* Also note that what ever the arrows are supposed to mean they have no special meaning in regular expressions. The arrows will be matched literally *) In the regex I am familiar with, as described above there are different styles.

Is this still regarding regular expressions?

Sorry, that is not very clear. Please explain, preferably with an example. There is something about the exercise formulation I do not understand. Two primes A and B have the product C=A*B. The product, C, can't be a prime.

Are you sure about the formulation? If you multiply primes from a sequence of primes how could the result be a prime number?

That work seems related to crop circles rather than concepts of mainstream science. I would recommend other sources such as those provided by @Phi for All.

That seems pretty close. Add the missing " after the string and the code will run:

https://www.w3schools.com/python/ref_string_find.asp

@MigL: Bug free images. When conditions are right the water from the gentle waves in the lake embeds the stones and vegetation in almost transparent ice bubbles. (Getting into a better position or angle to take the pictures was not worth the risk. Or maybe I was getting too old and lazy)

Probably. But more likely I tried to point out the holes in another members argument regarding outwards acceleration and I went off on a tangent.

Recently I returned to a discussion after a break and I was suddenly accused of not taking centrifugal forces into account. I guess I was out of the loop for a while.

I missed that the forum handles backlash + parenthesis specially. I meant: \(regexp\)

Today I learned that when analysing the system behaviour of a centrifugal clutch* both the fictitious centrifugal force and the reactive centrifugal force can be used. *) according to wikipedia: https://en.wikipedia.org/wiki/Reactive_centrifugal_force#Applications

I agree. Good list of special characters. Just an additional note @zak100: You never told us what you or your teacher uses so you need to be aware that in some cases the escaping differs among regular expression styles. Some platforms use backslash to escape parenthesis: \(regexp\).

Can you show us a reference where the teacher tells what kind of regular expression they use? Are you sure they actually discuss regular expression? It is a character. The regular expression U has a match in the text ”Us” but there is no match in the text ”Bar” In other words, there is nothing special about U. reference: https://www.rexegg.com/regex-quickstart.html

Ok. Then we can drop the examples and start from the basic. For instance what kind of regular expression you use. There are different variants with different syntax. If you want to use your own personal syntax you need to tell us all the rules you have invented.

Good point! Also points at the issues with the opening question. In regular expression union is represented by "|", it's not represented by the charter "U". @zak100 Maybe you could clarify if actually wish to discuss regular expressions* or something else? Its not obvious if you try to solve an issue with programming syntax or have a more general issue with sets, logic or similar. Also, just a friendly reminder; we are on a discussion forum, your short questions "please tell me", "please give examples" etc does not, in my opinion, promote fruitful discussions. They are more suitable for entering into a search engine for a quick and precise answer. *) https://en.wikipedia.org/wiki/Regular_expression