W katalogu filii wyszukam wydanie i egzemplarz.

Because w meaning in normally requires the locative case.

• basic form: katalog
• after w: w katalogu = in the catalogue

So katalogu is the locative singular form of katalog.

Here filii is most naturally understood as a genitive form linked to katalogu.

The phrase katalog filii means roughly:

• the branch’s catalogue
• or the catalogue of the branch / branches, depending on context

So the structure is:

• w katalogu filii = in the catalogue of the branch / branches

A useful thing to know: filii is an ambiguous form in Polish. It can represent more than one grammatical value, including:

• genitive singular
• genitive plural
• also some other non-nominative singular forms in other contexts

So only context tells you exactly whether it means of the branch or of the branches.

That is because wyszukam is from a perfective verb: wyszukać.

In Polish, perfective verbs do not normally have a true present tense. Their present-looking forms actually refer to the future:

• wyszukam = I will find/search up
• not I am searching up

So although the ending looks like a present-style personal ending, the meaning is future because of the verb’s aspect.

They differ mainly in aspect and nuance.

• szukam = I am looking for / I look for
• będę szukać = I will be looking for
• wyszukam = I will locate/find by searching

So wyszukać often suggests a successful or completed search, especially in places like:

• catalogues
• databases
• lists
• search tools

It is often closer to search up, locate, or find through searching than plain look for.

They are in the accusative case, because they are the direct objects of wyszukam.

• wyszukam co? = what will I search/find?
• wydanie i egzemplarz

Why do they look unchanged?

• wydanie is a neuter noun, and its accusative singular is the same as its nominative singular
• egzemplarz is a masculine inanimate noun, and its accusative singular is also the same as its nominative singular

So they are accusative here, even though their forms do not visibly change.

They are not the same thing.

• wydanie = edition
• egzemplarz = copy, usually a physical individual item

In a library context:

• wydanie refers to the publication version
• egzemplarz refers to a particular copy owned by the library

So the sentence is distinguishing between the edition itself and a specific copy.

Because Polish has no articles.

English needs words like:

• a
• an
• the

Polish normally does not use separate words for that. Whether something is definite or indefinite is usually understood from:

• context
• word order
• the situation being talked about

So wydanie i egzemplarz can mean an edition and a copy or the edition and the copy, depending on context.

No, Polish word order is relatively flexible.

This sentence has a natural, straightforward order:

• W katalogu filii — setting/location first
• wyszukam — verb
• wydanie i egzemplarz — object

But other orders are possible, for example to change emphasis. Polish often moves elements around to highlight what is new, important, or contrasted.

So this word order is natural, but not the only grammatical one.

Because w is the normal preposition for in / inside / within.

Here the idea is searching in a catalogue, so w katalogu is exactly the expected choice.

Compare the pattern:

• w książce = in the book
• w katalogu = in the catalogue
• w bazie danych = in the database

So w fits the idea of searching within a system, source, or contained space.

Yes, in the sense that both nouns stay in the same case because they are joined as a single coordinated object.

So:

• wydanie = accusative
• egzemplarz = accusative

The conjunction i simply means and, and both linked nouns match the role they play in the sentence. Since both are objects of wyszukam, both appear in the accusative.