Where the words come from
The definitions of monopoly and barriers to entry, natural and legal monopoly, control of a physical resource, patents, predatory pricing and the airline case — Principles of Economics 2e, OpenStax, licensed CC BY 4.0. https://openstax.org/books/principles-economics-2e/pages/9-1-how-monopolies-form-barriers-to-entry and https://openstax.org/books/principles-economics-2e/pages/9-introduction-to-a-monopoly. Changes: US examples (the Postal Service, AT&T, US patent law) left out or generalised; ALCOA named as "one company" and "aluminum" spelt "aluminium"; the airline predatory-pricing case condensed with the airline names left out; "retail space" to "a shop"; "neighborhood" to "neighbourhood"; "Legal protection" as a card name is ours for 2e's "legal monopoly" row; the predatory-pricing definition extends 2e's "threat of sharp price cuts" with our clauses on actual cuts below average cost and driving rivals out; the Royal Mail example, the drug example, the mistake note on the UK market-share sense of legal monopoly, the exam tip and checks are ours; the 25% merger-control line in the mistake note is ours; British spelling.
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