Başvuru dilekçesi eksik; dolayısıyla elektronik başvuru geçerli değil.

This is a very common Turkish pattern called an indefinite noun compound.

• başvuru = application
• dilekçe = petition / formal written request
• dilekçesi = dilekçe
  • the compound ending -si

So başvuru dilekçesi means application petition / application letter.

In this structure:

• the first noun stays plain: başvuru
• the second noun takes a possessive-type ending: dilekçesi

You see the same pattern in phrases like:

• öğrenci kartı = student card
• kimlik numarası = identity number
• başvuru formu = application form

So başvuru dilekçesi is the normal Turkish way to say this kind of compound noun.

Not here.

Although -si / -sı / -su / -sü can be a third-person possessive suffix, in a phrase like başvuru dilekçesi it is functioning as part of the noun-compound structure, not necessarily meaning his/her petition.

So in this sentence:

• başvuru dilekçesi = application petition

not

• his/her application petition

English does not really show this structure directly, so it can feel strange at first. A good way to think of it is: Turkish often marks the second noun in a noun-noun combination.

In Turkish, the verb to be is often omitted in the present tense, especially in the third person.

So:

• Başvuru dilekçesi eksik = The application petition is missing/incomplete.
• Elektronik başvuru geçerli değil = The electronic application is not valid.

This is completely normal Turkish.

If you want a more formal or emphatic written style, you can add:

• eksiktir
• geçerli değildir

But the version without them is very common and natural.

Eksik can mean:

• missing
• incomplete
• lacking

In official or administrative language, it often means that a required item has not been properly provided.

So Başvuru dilekçesi eksik could mean:

• the petition is not included
• the petition is incomplete
• some required part of it is missing

The exact English translation depends on context, but eksik basically tells you that something required is not fully there.

Both can relate to absence, but they are not the same.

• yok = there is none / it does not exist / it is not present
• eksik = missing / incomplete / lacking

Compare:

• Başvuru dilekçesi yok.
  = There is no application petition at all.

• Başvuru dilekçesi eksik.
  = The application petition is missing or incomplete as part of the file/process.

In official language, eksik is often preferred because it can cover both not submitted and not complete enough.

Dolayısıyla means:

• therefore
• consequently
• accordingly
• for that reason

Yes, it is fairly formal and very common in written Turkish, especially in administrative, academic, or official contexts.

In this sentence:

• Başvuru dilekçesi eksik; dolayısıyla elektronik başvuru geçerli değil.
• The application petition is incomplete/missing; therefore the electronic application is not valid.

Less formal alternatives include:

• bu yüzden
• bu nedenle
• o yüzden

But dolayısıyla fits official wording very well.

The semicolon shows that the two parts are closely connected:

1. Başvuru dilekçesi eksik
2. dolayısıyla elektronik başvuru geçerli değil

The second clause is the direct consequence of the first one, so the semicolon is a neat formal punctuation choice.

You could also write it as two sentences:

• Başvuru dilekçesi eksik. Dolayısıyla elektronik başvuru geçerli değil.

That would still be correct.

So the semicolon is mostly a matter of style and formality, not grammar.

Because in Turkish, adjectives come before nouns, just as in English.

So:

• elektronik başvuru = electronic application
• resmî belge = official document
• geçerli başvuru = valid application

If you put elektronik after the noun, it would not work as a normal adjective-noun phrase.

Then the predicate comes later:

• Elektronik başvuru geçerli değil.
• The electronic application is not valid.

So the structure is:

adjective + noun + predicate

Both are possible, and both can mean invalid.

• geçerli değil = not valid
• geçersiz = invalid

The difference is mostly one of style and tone:

• geçerli değil sounds a bit more explanatory and neutral
• geçersiz sounds a bit more direct, compact, and label-like

So these are both possible:

• Elektronik başvuru geçerli değil.
• Elektronik başvuru geçersiz.

In official notices, either one may appear. The version in your sentence is slightly more explicit.

Yes. That version is grammatically correct and sounds more formal and more official.

Compare:

• eksik / geçerli değil = normal written Turkish, still formal enough
• eksiktir / geçerli değildir = more bureaucratic, formal, and stiff

So:

• Başvuru dilekçesi eksik; dolayısıyla elektronik başvuru geçerli değil.
  = natural official style

• Başvuru dilekçesi eksiktir; dolayısıyla elektronik başvuru geçerli değildir.
  = even more formal and impersonal

You will often see both styles in announcements, legal language, and institutional messages.

Turkish does not use articles the way English does.

So:

• başvuru dilekçesi can mean the application petition or an application petition
• elektronik başvuru can mean the electronic application or an electronic application

The exact meaning comes from context, not from separate words like the or a.

That is why Turkish sentences can look more compact than English ones. When translating into English, you often have to decide whether the or a/an sounds best from the situation.