Consider the following statements regarding the society and culture of Punjab:

1. Punjab’s cultural identity is shaped by bravery, generosity, and religious harmony due to its historical interactions with various invaders.
2. Sikhism encourages an ascetic lifestyle, which has influenced the broader Punjabi way of life.
3. The Punjabi culture is an amalgamation of influences from the Indus Valley Civilization, Aryans, Greeks, and Islamic traditions.
4. Punjab’s history of invasions led to the development of multiple subcastes in the region.

Which of the above statements are correct?