@wikipedia.org
A specific property of a given function:
F(a_1 \cdot x_1 + a_2 \cdot x_2) = a_1 \cdot F(x_1) + a_2 \cdot F(x_2)
In general case:
F \left( \sum_{i=1}^N a_i \cdot x_i \right) = \sum_{i=1}^N a_i \cdot F(x_1)
Formal science / Mathematics