Unicorn A formalisation of the argument about the unicorn, an intuitive explanation of why it appears to be valid and a formal, deductive proof of its validity If the unicorn is mythical, then it is immortal, but if it is not mythical, then it is a mortal mammal. If the unicorn is either immortal or a mammal, then it is horned. The unicorn is magical if it is horned. The document also contains the following conclusion. The unicorn is magical. 1. Identify the atomic propositions. 2. Formalise the argument in propositional logic. 3. Using your intuition and your own words, explain (in English) why the argument appears to be valid. 4. Provide a formal, deductive proof of the validity of the argument. Every step of your proof must be numbered and fully annotated.