1. «جَاءَنِي عُمَرُ» — governor of ʿUmar: «جَاءَ»; role subject, case nominative.
2. «رَأَيْتُ عُمَرَ» — role object, case accusative.
3. «مَرَرْتُ بِعُمَرَ» — genitive governor «بِـ»; case genitive, sign fatḥa.
State the syntactic role before naming the case sign; do not infer the case from a vowel alone.