1. Economic Model of Copyleft Vira Lyubchenko Odessa National Polytechnic University

3. Model of Software Development The development stage Programmers choose their occupation The monopolist sets the wage Programs are produced and sold Consumers evaluate programs and the monopolist determines the price The output stage

6. Market for Copyright and Copyleft Programs Valuation Consumers M OR represents the number of consumers buying the copyright product V R V R – p – c = V L – c L R V Rj V L V R – p – c V L – c O RL represents the number of consumers acquiring the copyleft program

7. Market for Copyright and Copyleft Programs Valuation Consumers M V R V L V R – p – c V L – c O There are no consumers who would receive positive surplus from the copyleft program and the negative one from the copyright program. L R

8. Condition for Using Copyleft V Lj – c > 0 V Rj – p – c = 0  p > V Rj – V Lj V Rj = V Lj V R V L V Lj > c V R V L – 1 p > c

9. Statistical data (http://stats.iatp.org.ua)

10. Statistical data (cont.) (http://stats.iatp.org.ua)