A grammer generating {0ⁱ1^j2^k | i = j or j = k }

1. S Þ AB | CD
2. A Þ 0A1 | L
3. C Þ 0C | L
4. B Þ 2B | L
5. D Þ 1D2 | L

Discussion: The two cases i = j, j = k are set apart by the two options in production 1. Repeated application of production 2 provides equal number of 0 and 1 (the case when i = j). Similarly repeated application of production 5 provides equal number of 1 and 2 (the case when j = k). Production 2 along with production 4 produce the strings