Inheritance -- incremental modification

• Result = Parent + Modifier

Example: $R\; =\; \{\; a1,\; a2\; \}\; +\; \{\; a2,\; a3\; \}\; =\; \{\; a1,\; a2,\; a3\; \}$

Independent attributes: M disjoint from P
Overlapping attributes: M overrules P

Dynamic binding

• $R\; =\; \{...,P\_i:\; self\; !\; A,...\}\; +\; \{\; ...,M\_j:\; self\; !\; B,\; ...\; \}$