## Math 327, Professor Loring

#### Week One, Fall 2004

• I am out of town this week. My graduate student Dave Worth will give the first lectures.
• I won't have eMail access, but Dave will know how to forward questions to me.
• A general description.

#### Week Two, Fall 2004

• I'm back, but ill.
• Homework #1 (due September 8): §2.1, 1(b)(d), 5(b)(c)(e), 9(a); §2.2, 2(c), 3(b), 16; §2.3, 4(b), 6.

#### Week Three, Fall 2004

• Homework #2 (due September 17): §2.4, 2(c), 8(b), 13(b); §2.5 3(e), 5(b); §3.1 7, 10(b); §3.2 7(c)(d), 15(b).

#### Week Five, Fall 2004

• Homework #3 (due October 1): §4.1: 8; §4.2: 7, 9(b), 11(e), 22; §4.3: 10(b), 31(b).

#### Week Six, Fall 2004

• You'll get your tests back this Monday.
• Your test will show a letter grade, and the more accurate numeric grade on the "GPA scale."
• Info on UPCs from Wikipedia
• More in-depth info on check sums.
• Why the factor of 3 in the UPC checksum? This is so that the UPC system can detect most transpositions of adjacent digits. This has no benefit with the bar-code reader itself, but is there to protect against a common error when the code is manually entered.
• If there is interest, we can cover Verhoeff's Dihedral Group D_5 Check, which is designed to better defend against the errors common in human input of numbers. This was proposed in 1969, five years before the UPC was in use, so one wonders why it was ignored.

#### Week Twelve, Fall 2004

Homework #7, due Friday 11/19: §9.2 13, 14(b), 18, 20(b)(d)(f); §9.3 2(a), 9.