Logic Definition and 1000 Threads

1. Homework Statement Let L = {P } be a first-order language with a binary relation symbol P as only non-logical symbol. By exhibiting three suitable L-structures prove (informally) that no two of the following sentences logically implies the other (i) ∀x∀y∀z(P (x, y) → (P (y, z) → P (x...

Homework Statement http://www.play-hookey.com/digital/electronics/dl_gates.html revered members, in the above link, for OR GATE, when either of the diodes are forward biased we get the output voltage as logic HIGH. but for AND GATE, when when either of the diodes are forward biased or...

fuzzy logic can be emulated with "standard logic" if fuzzy logic can be emulated with "standard logic" then how can it be fundamentally different? shouldnt any newly proposed logic system, by definition, be impossible to model with another logic system? If you can emulate it then its not...

The following is from regulations regarding setting up a Roth IRA "Withdrawal of earnings prior to five years and age 59½ are subject to penalty and income tax." I read that to mean: Withdrawal of earnings (prior to five years) AND (prior to age 59½) are subject to penalty and income tax...

Assume ideal gas and isothermal : \Delta H = \int_{T_{i}}^{T_{f}}\! C_{p} dT = 0 (no change in temperature, no change in enthalpy) \Delta H = \Delta U + W, U = 0 There is no change in internal energy but there is change in work done. How do these two contradicting statements work.

I have ~(P&Q) and I want to get ~P v ~Q (& means and) (v means or) Am I right in thinking that I can: 1.~(P&Q) Main assumption Sub derivation 2..Assume P&Q 3.Reiterate ~(P&Q) End sub derivation 4.Then do 1-2, ~I (negation elimination) to get ~P 5.then do vI (disjunction...

Hi all, I was puzzled by the answers offered by an assessment book on this 2 questions. Hope fellow forummers can help me out on this please. 1. A thin steel card is made to vibrate by holding it against the teeth of a cog wheel. The wheel is rotated with increasing speed. The sound wave...

Homework Statement Assume you have a symmetrical clock at 100MHz. Design a logic circuit with four outputs of clocks at 100MHz, 50MHz, 25MHz, and 12.5MHz. The logic circuit should have 2 inputs to select output clock rate. Homework Equations N/A The Attempt at a Solution For...

Homework Statement Using NAND, AND OR, &/or NOR gates build a vote counting machine. It should light an LED when majority votes are true (or answer "yes"). Assume 4 input votes only. Homework Equations Boolean Logic The Attempt at a Solution So I know the solution in terms of...

Do a derivation showing that (P conditional Q) v P is a theorem of system SD+ *Sorry guys, I can't figure out how to do the symbol in between (P Q), but it means If P then Q and it is otherwise known as the conditional -I am really struggling with this problem and I would greatly...

I am confusing the heck out of myself here. This is what I have Square matrix that is M = 'm x m' A column vector that is C = 'm x 1' a smaller square matrix that is R ='r x r'Here is what I am trying to accomplish; I usually do this by hand: The entries of the column vector C are either 1...

Homework Statement Ive been asked to create a roaming 7 day alarm for college. This alarm must trigger a lamp (output), after the input, which i am using to simulate an alarm, has been pressed 10 consecutive times in a 7 day period. if it is pressed less than 10 timesin a week, then any...

Hi PF. This is a homework question, but it's for symbolic logic. Figured that it didn't really make sense to post it with the math and science questions, although I'm sure people on there would know how to solve it. I'm having trouble constructing a derivation for the following: For all x...

Every few years I Google this book and then ask about it book here on PF on the off-chance that someone recognizes it. I cannot nail down anything specific that Google can work with, so ultimately it fails. I'm going to try something different this time that should improve my Google search...

Hi there, I'm having some issues with logic functions in matlab. I don't use them very much so I'm not too familiar. What I'm trying to do is create an 'm' file for a physics project and I would like a certain progression. I'm trying to create some 'if' statements to do this. So first of all I...

pretty new to this whole computer architure thing, so i appreciate the answers given to my previous question, went through a lecture today in class, came out pretty clueless...what i would like to know is how exactly would the block diagram for a four bit adder circuit look? thank you for...

Clarification: Not a religious god, but the first force. Starting question: What was the original cause that started everything, how can there be an original cause without god? Case A: There was no original cause; the universe always was and always will be. Result: No god. Case B...

What do "two-level" and "multi-level" gate circuits mean? I have been doing questions relating to logic gates circuits, and have noticed that some questions say "implement with two-level NAND gate circuts" And then a different question would say "implement with multi-level NOR gate...

When it is fitted to supernova observations, our standard picture of the cosmos tells us that the current boundary of the universe which can affect us is at z = 1.73. As of today, no event that occurs beyond that limit can ever be known to us or have any causal effect. This is primarily based...

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...

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...

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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...