Acknowledgements ================ We would like to thank Daniel Jackson for suggesting some of the examples used in this book. This work was financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation - COMPETE 2020 Programme and by National Funds through the Portuguese funding agency, FCT - Fundação para a Ciência e a Tecnologia, within project `POCI-01-0145-FEDER-016826 `_.