Zero Present Copula

Unlike English, which requires 'am/is/are', Ukrainian typically leaves the verb бути (to be) unsaid in the present tense. This is a standard grammatical feature rather than an omission.

1. Subject — Predicate Constructions
When both the subject and the predicate are nouns, infinitives, or numerals, a dash (—) is generally used in writing to represent the missing verb and a pause in speech. However, this rule is subject to specific exceptions regarding word order and intervening words (see sections 5 and 6).
Example: Київ — столиця. (Kyiv [is] the capital). Жити — вітчизні служити. (To live [is] to serve the motherland). Два плюс два — чотири. (Two plus two [is] four).

2. The 'це' Construction
A very common way to identify things is using це (this is). When це, or similar particles like то, ось, or значить, are used between the subject and the predicate, a dash is mandatory and is placed before the particle.
Example: Київ — це столиця. (Kyiv — this is the capital).

3. Pronoun and Adjective Constructions
If the subject is a personal pronoun (like він) or an interrogative pronoun (like хто or що), or if the predicate is an adjective, the dash is usually not required. Similarly, demonstrative pronouns acting as subjects (like це or то) usually do not take a dash in neutral sentences.
Example: Він лікар. (He [is] a doctor). Вона щаслива. (She [is] happy). Це мій дім. (This [is] my home).
However, if the speaker wants to place strong logical emphasis or a significant pause on the pronoun or the adjective, a dash is used.
Example: Я — українець! (I [am] a Ukrainian!). Найдорожча пісня — недоспівана. (The most precious song [is] the unsung one).

4. The 'не' Exception and Contrast
A dash is typically not used when the negative particle не precedes the predicate.
Example: Серце не камінь. (The heart [is] not a stone).
However, the dash is kept if there is a direct contrast using а (but), or simply for strong logical emphasis and intonation.
Example: Він — не лікар, а вчитель. (He [is] not a doctor, but a teacher). Кров — не вода. (Blood [is] not water).

5. Comparatives and Inverted Word Order
The dash is also omitted in two other specific cases:
- Comparisons: When the predicate is introduced by comparative words like як, мов, or ніби. Example: Очі як зорі. (Eyes [are] like stars).
- Inverted Word Order: When the predicate comes before the subject. Example: Чудова людина мій сусід. (A wonderful person [is] my neighbor).

6. Intervening Words and Secondary Members
The dash is typically omitted if there is an adverb, particle, introductory word, or a secondary sentence member (like an object) between the subject and the predicate.
Example: Київ тепер столиця. (Kyiv [is] now the capital). Цей словник, безумовно, корисний. (This dictionary [is], undoubtedly, useful). Хліб усьому голова. (Bread [is] the head of everything).

7. Fixed Idiomatic Expressions
A dash is not used when the subject and predicate form a set phrase or idiom.
Example: Два чоботи пара. (Two boots [make] a pair).

8. The Role of 'є'
While the overt form є is primarily used for existence and possession, it is not strictly forbidden for identification. In formal, scientific, or legal definitions, є is often used to add emphasis or clarity. Note that in these formal contexts, the predicate noun often shifts to the Instrumental case.

9. Case Requirements
In standard zero copula identification, the predicate noun or adjective stays in the Nominative case. This is a crucial distinction from the past or future tenses, where the Instrumental case is typically used.