є (екзистенційне)

In Ukrainian, the present tense copula is typically a zero copula. However, є is used in specific contexts:

• Existence: To state that something exists or is present. In these sentences, є usually comes before the subject. Example: Є проблема (There is a problem).
• Possession: In a standard possession construction (у/в + Genitive + є + Nominative), which is interchangeable with the verb мати (to have) + Accusative. Example: У мене є час (I have time). In spoken Ukrainian, possession questions often drop the pronoun entirely if the context is clear (e.g., Є час? or Є питання?).
• Emphasis: To emphasize the reality of a fact. When є is explicitly used to link a subject to a noun, the predicate noun is often put into the instrumental case. Example: Він є лікарем (He is a doctor) or Я є українцем (I am a Ukrainian).

Key Rules:
1. Invariance vs. Agreement: Unlike other verbs, є is 'frozen' in the present tense. You use it for both singular and plural subjects (e.g., є книга and є книги). This contrasts with the past and future tenses of 'бути': the past tense must agree with the subject in gender and number (e.g., був/була/було/були), while the future tense agrees in person and number (e.g., буде/будуть). Crucially, in past and future possession constructions, the verb agrees with the possessed object (the grammatical subject), not the possessor (e.g., У мене була машина - I had a car).
2. Existence vs. Location: Use є to state that something exists (Тут є стіл - There is a table here). However, omit є when stating where a specific, known object is located (Стіл тут - The table is here).
3. Case: In affirmative sentences, the thing that exists must be in the nominative case.
4. Negation: You cannot negate this with 'не є'. Instead, you must use the special word немає (or its common shortened form нема) followed by the genitive case. For past and future negation, use не було and не буде respectively, also followed by the genitive case (e.g., У мене не було машини - I didn't have a car).
5. Adjectives in Possession: It is perfectly natural and standard in Ukrainian to keep є when the possessed object is modified by an adjective. For example, У мене є нова машина (I have a new car) is completely standard, unlike in some neighboring languages where the copula might be omitted.