🔗 Definition 2.3.2. 🔗A PSET is a collection of 3 cards such that the cards may be flipped over in such a way so that both the top and the bottom form SETs.
🔗 Activity 2.3.4. 🔗(a) 🔗What card(s) can you add to form a PSET? 🔗(b) 🔗Out of these cards, how many PSETs can you find?🔗(c) 🔗Pick any two cards, can you find what card(s) if any will complete a set? How many PSETs can you find? Repeat.
🔗(c) 🔗Pick any two cards, can you find what card(s) if any will complete a set? How many PSETs can you find? Repeat.
🔗 Remark 2.3.4. 🔗We will let a Pline in the PSET context to be a collection of 4 cards so that every 3 card subset forms a PSET.
🔗 Activity 2.3.5. 🔗(a) 🔗Pick any three cards who do not form a PSET and arrange them in a corner of the 3×3 grid: 🔗(b) 🔗Fill out this grid so that each line forms a Pline.🔗(c) 🔗For each pair of cards on this grid, do they lie on exactly one Pline?