In what grammatical context is the genitive case obligatory with negated verbs in Russian, even when the direct object is typically accusative?

The genitive case becomes obligatory in Russian with negated transitive verbs when the direct object represents an abstract or uncountable noun, or when the negation encompasses the existence or availability of the object rather than a specific action performed upon it. Transitive verbs are verbs that take a direct object. Normally, a direct object would be in the accusative case. Negation involves adding 'не' (ne) to the verb, creating a negative statement. For instance, instead of....