Do not continue to work on or revise your assignment once you are in the classroom.
Fill out the self-evaluation form and turn it in as soon as you have filled it out.
The class today will be devoted to discussing and refining a first set of proofs of 3 propositions. The class will be divided into 6 groups and into 2 half-classes. One half-class of 3 will work with King and one half-class of 3 will work with Treisman.
Each group will discuss the proofs of the 3 propositions listed below. Since there may not be time to cover all 3, the order of discussion will vary from group to group (you will be assigned the order for your group). You will NOT rewrite or edit your homework paper. You can refer to it, but you will write on a fresh sheet of paper.
In each group you will try to come to a consensus as to a correct proof for your first proposition. Then you will write down the proof and make sure that everyone understands it. Then as time permits, you will move on to the next and then the third propositions.
Each group will present at the board its first proposition. The presentation will be made to the half-class of the group. The presentation time will be about 5 minutes.
Your work for Assignment 1A will be evaluated for an "effort grade" during class today. You will turn in Assignment 1A along with Assignment 1B on Monday. It is OK to rewrite your proofs if you feel that your original effort should be improved.
Let ABC be any triangle. (1) If angle B = angle C, then AB = AC. (2) If AB = AC, then angle B = angle C.