### INTRODUCTORY-CHALLENGE-PROBLEM-2

challenge problem 2 for the new user of ACL2
Major Section: INTRODUCTION-TO-THE-THEOREM-PROVER

Start in a fresh ACL2, either by restarting your ACL2 image from scratch or
executing `:ubt! 1`

.

Use The Method to prove

(defthm subsetp-reflexive
(subsetp x x))

When you've solved this problem, compare your answer to ours;
see introductory-challenge-problem-2-answer.

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