Questions tagged [discrete-mathematics]

The study of discrete mathematical structures. Consider using a more specific tag instead, such as: (combinatorics), (graph-theory), (computer-science), (probability), (elementary-set-theory), (induction), (recurrence-relations), etc.

Discrete mathematics is not the name of a branch of mathematics, like number theory, algebra, calculus, etc. Rather, it's a description of a set of branches of math that all have in common the feature that they are "discrete" rather than "continuous".

The term "discrete mathematics" is therefore used in contrast with "continuous mathematics," which is the branch of mathematics dealing with objects that can vary smoothly (and which includes, for example, calculus). Whereas discrete objects can often be characterized by integers, continuous objects require real numbers.

Though there cannot be a definite number of branches of Discrete Mathematics, the following topics are almost always covered in any study regarding this matter −

  • Sets, Relations and Functions
  • Mathematical Logic
  • Group theory
  • Counting Theory
  • Probability
  • Mathematical Induction and Recurrence Relations
  • Graph Theory
  • Trees
  • Boolean Algebra

For an overview, see the Wikipedia entry on Discrete mathematics.

and http://www.cs.yale.edu/homes/aspnes/classes/202/notes.pdf

Consider using a more specific tag instead, such as: , , , , , , , , etc.

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Discrete Math - Translating from English to Logic

Use E(x) for “x is even” and O(x) for “x is odd.” Question: One more than any odd number is an even number. Answer: ∀x [O(x) ⇒ E(x+1)] Could anyone verify my answer please? Thank you
Pablo Esco
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Not following what's happening with the exponents in this proof by mathematical induction.

I'm not understanding what's happening in this proof. I understand induction, but not why $2^{k+1}=2*2^{k}$, and how that then equals $k^{2}+k^{2}$. Actually, I really don't follow any of the induction step - what's going on with that algebra?…
user56763
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Derive the following identity $1^2+2^2+ \ldots + n^2 = \frac{n(n+1)(2n+1)}{6}$.

Count the elements of the following set $$A=\{(x,y,z): 1\leq x,y,z \leq n+1, z>\max\{x,y\}\}. $$ From this derive the following identity: $$1^2+2^2+ \ldots + n^2 = \frac{n(n+1)(2n+1)}{6}.$$ In the same manner find the formula for $1^k +…
Jack Blackwell
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About prove this statement is true or false

$P(x): x ≤ 0,$ $Q(x): $x^2$ = 1,$ $R(x): x $ is odd, $S(x): x = x + 1.$ Statement: $∀x ∈ Z, S(x) → R(x) \;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;(1)$ $∃x ∈ Z$ such that $Q(x) ∧ ∼ R(x) \;\;(2)$ $∃x ∈ Z$ such that $P(x) → S(x) \;\;\;\;(3)$ I try to let $x$…
TomAsh
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Mathematics to learn for applying for undergraduate computer science

What are the resources, books or papers you would recommend that would help me 'wow' Computer Science undergraduate admissions when I apply next year?
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How does this read: Ex P(x)

Let P(x) be the statement "x + 1 = 2x" domain is all integers, what is the truth value? $\exists x P(x) (E should be backwords...) I know how to do P(0). But how exactly do I do this one? I wouldn't just want a True or False. Please explain how…
KKendall
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Mathematically, is there a highest possible compression level for given data?

Assuming we found a perfect lossless data compression algorithm, can we prove that this algorithm would only be able to compress given data to a certain size?
Tsing Shi Tao
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determining an effective and correct way to mathematical problem

I have a task on hand and have been struggling to get the right number. Here is what I'm working with.. Part A $63,569.60 <-- my goal to achieve (as close as possible, hopefully within cents). Part B 277104 My goal is I need to update 277104 units,…
Koosh
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Which branch of mathematics studies the parameters of logical problems?

Suppose I have the following problem: $2$ kids are liars, $3$ can only say the truth. Julia: "Jack is only a liar, if John is telling the truth Jack: "If Joey doesn't lie, then either Julia or John do Joey: "Jane lies, as does Julia or…
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What does consistency mean in Mathematics?

What does consistency mean in Mathematics? Does the meaning vary as per the context? If yes, than can you give some examples? PS: I'm not sure what is the correct tag for this question, please someone edit it. Thank you so much :)
William
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Inverse z transform - help understand left sided region

Attached a snapshot of problem and solution at the bottom. Need to find the inverse of the given function. I perfectly understand how they got the right-sided sequence by differentiating below : $$\dfrac{1}{1-z^{-1}} =…
AgentS
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Equation with n on bottom with a0=0 and a1=1

I have this equation $a_{n+2}=a_{n+1}+6a_n$ for $a_0=0,a_1=1$. I should $a_{0+2}=a_{0+1}+6a_0$ (1) relation.The case $a_1=1$ it should be $a_{1+2}=a_{1+1}+6a_1$. I just replace it. What should I have done?
ek.Sek
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Can we predict the theorem we need when making a proof?

Sometimes when I’m proving a mathematical problem, I might find out that i still need some hints(some important theorem, hypothesis,etc). Is there any possibility to know(to predict) what we need in the proof? Can the model theory solve this…
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Freq. Response of Discrete System

Let's say that I have the following continuous system: $$G(s)= \frac{2}{1+s}$$ I could convert it to a discrete system using for example the Tustin approximation https://en.wikipedia.org/wiki/Bilinear_transform So I replace s with: $$s…
james
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Binary relations, transitivity and symmetry

While studying about binary relations, I got confused while solving some simple problems. For example: Let $R=\{(a,a), (a,c), (b,b), (b,c), (c,c), (c,a), (c,b), (d,d)\}$ be a binary relation on the set $A=\{a, b, c, d\}$ Are $\{(a,c), (c,a)\}$ and…
Glauvus
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