Logic Definition and 1000 Threads

Hi All, I know that the environment is responsible for people of African descent having black skin and people of Scandinavian descent have white skin but I cannot figure out the logic behind this. I thought it had to do with the absorption of Vitamin D from the sun and the Scandinavian...

I wasn't sure whether to post this in the algebra forum or here, but it seems that this is more of a logic question so I'm going with here. I am trying to understand whether there is a difference between the following two definitions of an equivalence relation: Definition 1: A binary relation...

I was given a truth table and I must write a wff with exactly two two-place connective. I am new to logic and don't know where to start. I need to find wff a), b), c) and d). C B A ... wff a) T T T ... T T T F ... F T F T ... T T F F ... F F...

Hello, i had a quick question, basically i am trying to build a 4 bit full adder logic circuit on a motherboard. i been trying to research but i came up empty...i would like to know what are the exact parts that i need to successfully build this logic circuit? thanks..

Homework Statement I've been given a problem: "C(x,y) is x and y have chatted over the internet. The domain is students in a class. Express there are two students who combined have chatted with all of the students in the class".2. The attempt at a solution I think this is the correct answer...

I don't even know if this post is in the right place but I'm going to give it a shot anyways. I am supposed to draw a ladder diagram that controls L1, L2, and L3. L1 is supposed to come on the first time the start button is pushed. The second time the start button is pushed, L1 and L2 are...

Homework Statement Determine whether \existsx\forally[p(y) --> q(x)] is equivalent to \forally\existsx[p(y) --> q(x)], justify your answer with a proof. Homework Equations The Attempt at a Solution I know that when you switch quantifiers in something like P(x,y), the meaning...

Hi all,:cool: how do we implement any given circuit with the help of NAND and NOR gates??

Homework Statement I have attached a jpeg image of a karnough map of a rs flip flop. How can i derive the logic equation? Homework Equations The Attempt at a Solution

Homework Statement I actually have to problems I would just like someone to confirm for me. I have several other problems similar to these, and I don't want to waste time in case I do not understand the fundamentals. Anyway: a) Define suitable predicates and functions and then formalize...

With finite amount of sets unions and intersections can be written as A_1\cup A_2\cup\cdots\cup A_n and A_1\cap A_2\cap\cdots \cap A_n. If we have an arbitrary collection of sets, (A_i)_{i\in I}, then we can still write unions and intersections as \bigcup_{i\in I} A_i...

A lot of times, when I look at something written in logic, there are these strange symbols popping out everywhere. Examples include an upside-down A, a giant V or U, or an upside-down V. Could you point me to an article describing what these symbols mean?

Hey so I am doing a grad course on logic and skipping the undergrad introductory course. My friends have said that I will be fine but I want to get a head start and read some of what I missed in the undergrad class. here is the description for it. Elementary development of propositional and...

Homework Statement let p, q, and r be the following propositions p: You get an A on the final exam. q: You do every exercise in this book r: You get an A in this class translate: You get an A on the final, but you don't do every exercise in this book; nevertheless, you get an A in...

I want to use 24v to break 120v loads. I understand the logic for dc circuits but I am not sure how to break 120v loads. What relay do i use? I was looking at the altronix RAC120 or RAC24. Do I break just the hot leg of the 120v? Any help on such a beginner question would be...

I know that if you have x-2, that's the same thing as saying 1/x2. But I'm just wondering what is the mathematical reasoning for why that's true? Thanks!

what do you think about this game: similarly like in Mastermind and Super Mastermind computer gives informations but in this game such informations is a lot more: - two in vertical corners on place - two in vertical corners not on place - vertical three (counting from top) on place...

I am looking into some automation of basic tasks, and think that a PLC is the best approach. http://www.entertron.com/ This is a site that another forum recommended. Has anyone else used anything from these guys in the past? I have very very basic programming skills and need something...

Homework Statement https://www.physicsforums.com/attachment.php?attachmentid=21977&stc=1&d=1258886072 I think my proof is lousy and may be wrong. Please help me with it (= Thanks in advance Homework Equations My proof is of below. The Attempt at a Solution

Homework Statement Formalize (in PL) the relations/predicates stated in (a)-(e) using just these relations/predicates: 1) Pxy: x is a parent of y 2) Fx: x is a female 3) Sxy: x is a sibling of y (a) x is an uncle of y (b) x is a great-aunt of y (c) x is an aunt (d) x is a great-uncle (e) x...

how do i prove the following is a theorem in SD [(A -> B)->A]->A ... i started off by assuming [(A -> B)->A] then assume ~A to try to derive A in the end... but now I'm stuck :( and also: Suppose we dropped from SD the rule for vE, and adopted in its place the rule of Disjunctive...

Hello Forum , please can someone help me to design the hardware of this table of logic (by the use of the logic gate) , the table is in the attachment. Thanks in advance

Homework Statement 1. Is there any difference between the following 2 signs? <=> (for biconditional) and 三(the equivalence sign) 2. When we say 'P is defined as Q), do we mean P三Q? Thanks J Homework Equations The Attempt at a Solution It seems that for 2 propositions, P...

24. The logic expression A ⋅ (B +C) is equal to A. A +B +C B. A +B ⋅C C. A +B ⋅C D. (B) and (C) E. None of the above 25. The expression F = A + AB + ABC is equivalent to A. F = AB+B+ABC B. F = A+B+C C. F = ABC D. (B) and (C) E. All the above 32. The logic equation A + A·B + B·C + C is equal...

Hi Im having some difficulty with one of my coursework questions on programable array logic (PAL) design. If anyone could help with this it would be very much appreciated! The question is- Decoding logic is to be used to generate a logic 1 when the counter output indicates the number...

I always have difficulty with logic puzzles. Usually, I miss making inferences that really make the puzzle's solution flow out. Are there any good books/resources that train people on logic puzzles? (I moved this from the brain teaser forum) The kind of puzzle I'm talking about would go...

Moved.

I've been debating whether 0.9[R] does in fact equal 1. I've seen a lot of mathematicians saying it does and I believe that it is true that 0.9[R]=1, however it doesn't seem logical, as in, from my very low level of math I can seemingly find a way to disprove it. That would be this: If 0.9...

Mathematical logic-- need some suggestion I'm planning to start self-study of mathematical logic and axiomatic set theory. In fact I have already started and but facing a lot of problems to grasp the conception and formalism used there. After studying Hilbert's program and Godel 's...

Hi, Right now I am currently going through Set Theory and Logic by Stoll. This is my first time going through Set Theory, Logic, and everything else in the book. I feel like I'm not getting all I can out of this book because I don't feel like I'm on the same level, I struggle to answer the...

This is a cool riddle of logic that I heard recently. It is supposed to be drawn out so I'll try to describe it as best as I can. Four prisoners of war are sentenced to death by firing squad. They line them up from north to south, all of them facing north (so that they are in line facing...

Homework Statement Either A or B (names changed) stole the exam answers. Formalize these and check if this is a correct deduction: 1) If A didn't meet B for lunch, then B is guilty or A lives in the countryside 2) If B isn't guilty, then A didn't meet B for lunch and the incident happened...

Homework Statement Can anyone prove the following p <=> q Is equivalent to: (p ^ q) V (¬p ^ ¬q)

Homework Statement I want to construct a truth table for the following propositions Homework Equations (a) ¬p ∨ q (b) p ∧ q ⇒ p (c) ¬p ∨ q ⇔ p ⇒ q The Attempt at a Solution Approach: 1) Determine the order of precedence: 2) Fill in the values for the operator...

Dear Forum Users, I came across these three logic series' and as I was unable to resolve them, I thought about posting them here. Maybe you know the correct answers and care to explain? Sorry for the bad quality, but you should be able to recognise the patterns. thanks, Frohmeier...

This from Alonzo Church's Mathematical Logic, been stuck on it for a week =(. Homework Statement 14.3 Present a Formal Proof: p \Rightarrow (q \Rightarrow r) \Rightarrow ((p \Rightarrow q) \Rightarrow r)Homework Equations The Attempt at a Solution A truth table has shown that the previous...

I have this challenge to do but can't seem to be able to understand it completely! I also have test right now and can't concentrate. Please help this poor soul! It will be appreciated! The first question is:Let F ∈ PROP. Let (h)F be defined by the number of parentheses in the formula F. a)...

What is the mean of " Effective logic inversion " ? Because I can't understand this qustion, " Describe briefly why there is an Effective logic inversion between logic level from a TTL IC and the LED load it drives? "

Homework Statement Let |A| denote the weight function in this way: |=>|=|⋁|=|⋀|=|<=>|=+1 | ┐|=0 |p|=|r|=|s|=-1 Now I need to show that one statement to be logic statement the sum of all symbols need to be -1, and the sum of the symbols in every series, starting from A is non-negative (i.e...

I know this is probably in the wrong board, but. I'v just been looking into some Boolean algebra to convert truth tables into a set of logic gates representing a circuit. If i were attempting to represent a certain truth table, but i was limited to ONLY using NAND gates. (their the only...

I have been trying to familiarize myself with a particular system of first-order logic with identity, in which the process of substitution is achieved by replacing, one at a time, one occurrence of a variable with a term. (see axiom schemes 6) and 7)). I want to use these axioms to prove the...

1. Mark as true or false. The implication "If P, then Q " is equivalent to: a) P is necessary for Q b) Q is sufficient for P c) P is sufficient for Q d) Q is necessary for P e) P only if Q f) Q only if P It seems like there's missing something..If P is what? I don't get this...

I've been reading articles on logic gates and What I want to do before I get to school is familiarize myself with what individual components are used in making those individual gates on say a breadboard.I keep searching for it on the web but it just gives me the schematic symbols and not what...

Dear All, Having trouble with a seemingly simple logic truth table. Are these answers correct? \begin{tabular}{| c | c | c | c | c | c |} \hline p & q & r & (p \vee q)\wedge(q \vee r) & (\neg p \wedge q) \vee ( p \wedge \neg r) & p \rightarrow q \rightarrow r\\ \hline T & T & T...

Dear All, Having trouble with a seemingly simple logic truth table. Are these answers correct? \begin{tabular}{| c | c | c | c | c | c |} \hline p & q & r & (p \vee q)\wedge(q \vee r) & (\neg p \wedge q) \vee ( p \wedge \neg r) & p \rightarrow q \rightarrow r\\ \hline T & T & T & T & F...

Working on a homework for a general astronomy class. Just want to make sure I'm not being inaccurate. Please let me know if I goofed something up. Thanks! RQ7: The word “apparent” in “apparent visual magnitude” is used to denote its dependence on viewing distance. These numbers refer to...

M_{12}=\frac{N_2\phi _{12}}{I_1} i need to remmeber it but i can't see the logic of the formula ??

Hi guys, I have searched the forums but I don't think what I really would like to ask is covered :D. I would really like to find a book for self study on introductory Mathematical Logic, I am not really looking for anything covering Sets Or Number theory (unless of course the text is really...

The book which i read for improving my logic sense~ There is a theorem called REPLACEMENT .. ( P \rightarrow Q ) \vee \neg ( P \rightarrow Q) where (P\rightarrow Q) is the second occurence of ( P \rightarrow Q) But what if the replace the second occurrence with \neg P\vee Q! And i try...

Does anyone know if there is a relationship between the requirement in Quantum Computing that logic gates be reversible and the requirement in Quantum Mechanics that observables have to be self-adjoint?