Question

C. RETROACTIVITY OF LAWS (Civil Code, Art. 4), Vested Rights Principle

Scenario:

1. Arnold, a businessman, entered into a contract with Betty, a supplier, on January 1, 2020. The contract stated that Arnold shall pay Betty a fixed amount within 30 days of receiving the goods. However, on February 1, 2020, a new law was enacted amending the Civil Code. The amendment provides that in commercial contracts, the payment shall be made within 15 days. Arnold received the goods on January 15, 2020 and failed to pay Betty on time.
2. Martha applied for a building permit to construct a house on January 31, 2020. The local government approved her application on February 15, 2020 and issued the permit. However, on February 10, 2020, a new regulation was implemented requiring additional documentation for all building permits. Martha failed to comply with the new requirement.

Question:

Based on the given scenarios:

1. Discuss the retroactivity of laws under Article 4 of the Civil Code. Cite the provision and explain how it applies to Arnold's situation.
2. Explain the concept of vested rights principle. Analyze Martha's situation and whether the implementation of the new regulation can affect her right to the building permit.