maths.free › Combinatorics & Graph Theory › Inclusion-Exclusion › Discussion

Discussion

Yolanda said This seemed like a very short chapter, at least it did to me. Bob agreed Yes, but the professor indicated that the goal was just provide some key examples.

Discussion

Yolanda said This seemed like a very short chapter, at least it did to me. Bob agreed Yes, but the professor indicated that the goal was just provide some key examples. I think he was hinting at more general notions of inversionalthough I haven't a clue as to what they might be.

Clearly aggravated, Zori said I've had all I can stand of this big integer stuff. This won't help me to earn a living. Xing now was uncharacteristically firm in his reply Zori. You're off base on this issue. Large integers, and specifically integers which are the product of large primes, are central to public key cryptography. If you, or any other citizen, were highly skilled in large integer arithmetic and could quickly factor integers with, say \(150\) digits, then you would be able to unravel many important secrets. No doubt your life would be in danger.

At first, the group thought that Xing was way out of boundsbut they quickly realized that Xing felt absolutely certain of what he was saying. Zori was quiet for the moment, just reflecting that maybe, just maybe, her skepticism over the relevance of the material in applied combinatorics was unjustified.

Nu är det din tur. Ingen miniräknare bestämmer detta, men bitarna i det är beräkningsbara. Prova en nedan, eller skriv din egen.

Fortsätt jobba.

Ett gratis konto lägger till anteckningar om varje lektion, en förteckning över vad du har avslutat, dina lösta problem på ett ställe, och en handledare du kan fråga om denna sida. Matematiken i sig är öppen för alla, inloggad eller inte.

Registrera dig Inloggning

Symboler som används här

Knacka på alla symboler för den fullständiga definitionen, en bild, och vad varje bokstav i den betyder.

Frågor folk frågar

Permutation or combination?

Ask whether order matters. A lock code is a permutation (order matters); a hand of cards is a combination (it does not).

What is a graph in this sense?

Dots (vertices) joined by lines (edges), not a plot. Road maps, social networks and molecules are graphs; questions like "is there a route" and "how few colours" are graph theory.

Delar av denna sida är anpassade från Keller & Trotter, Applied Combinatorics (CC BY-SA 4.0). Kondenserad och återförklarad här; felen är våra.

Mer information Combinatorics & Graph Theory