So the number of permutations of [latex]n[/latex] objects taken [latex]n[/latex] at a time is [latex]\frac{n! Number of Combinations and Sum of Combinations of 10 Digit Triangle. What's the difference between a power rail and a signal line? The symbol "!" Draw lines for describing each place in the photo. So it is like we are ordering a robot to get our ice cream, but it doesn't change anything, we still get what we want. Continue until all of the spots are filled. So, in Mathematics we use more precise language: When the order doesn't matter, it is a Combination. How do we do that? In fact the three examples above can be written like this: So instead of worrying about different flavors, we have a simpler question: "how many different ways can we arrange arrows and circles?". 3) \(\quad 5 ! When you say 'k subsets of S', how would one specify whether their subsets containing combinations or permutations? But many of those are the same to us now, because we don't care what order! How many ways can 5 of the 7 actors be chosen to line up? This selection of subsets is called a permutation when the order of selection is a factor, a combination when order is not a factor. Permutation And Combination method in MathJax using Asscii Code. If there are 2 appetizer options, 3 entre options, and 2 dessert options on a fixed-price dinner menu, there are a total of 12 possible choices of one each as shown in the tree diagram. She will need to choose a skirt and a blouse for each outfit and decide whether to wear the sweater. This is the hardest one to grasp out of them all. The [latex]{}_{n}{C}_{r}[/latex], function may be located under the MATH menu with probability commands. \(\quad\) b) if boys and girls must alternate seats? Substitute [latex]n=4[/latex] into the formula. The general formula is as follows. We then divide by [latex]\left(n-r\right)! Lets see how this works with a simple example. This is like saying "we have r + (n1) pool balls and want to choose r of them". Is Koestler's The Sleepwalkers still well regarded? You could use the \prescript command from the mathtools package and define two commands; something along the following lines: I provide a generic \permcomb macro that will be used to setup \perm and \comb. Occasionally, it may be necessary, or desirable, to override the default mathematical stylessize and spacing of math elementschosen by L a T e X, a topic . Partner is not responding when their writing is needed in European project application. So (being general here) there are r + (n1) positions, and we want to choose r of them to have circles. Some examples are: \[ \begin{align} 3! 6) \(\quad \frac{9 ! If you want to use a novel notation, of your own invention, that is acceptable provided you include the definition of such notation in each writing that uses it. Then, for each of these \(18\) possibilities there are \(4\) possible desserts yielding \(18 \times 4 = 72\) total possibilities. What does a search warrant actually look like? There is a neat trick: we divide by 13! }{6 ! We commonly refer to the subsets of $S$ of size $k$ as the $k$-subsets of $S$. Is there a more recent similar source? Would the reflected sun's radiation melt ice in LEO? * 7 ! [latex]\begin{align}&P\left(n,r\right)=\dfrac{n!}{\left(n-r\right)!} Consider, for example, a pizza restaurant that offers 5 toppings. [latex]\dfrac{6!}{3! There are [latex]C\left(5,1\right)=5[/latex] ways to order a pizza with exactly one topping. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. In this lottery, the order the numbers are drawn in doesn't matter. Instead of writing the whole formula, people use different notations such as these: There are also two types of combinations (remember the order does not matter now): Actually, these are the hardest to explain, so we will come back to this later. Use the addition principle to determine the total number of optionsfor a given scenario. Follow . After choosing, say, number "14" we can't choose it again. The Addition Principle tells us that we can add the number of tablet options to the number of smartphone options to find the total number of options. If your TEX implementation uses a lename database, update it. There is [latex]C\left(5,0\right)=1[/latex] way to order a pizza with no toppings. We can have three scoops. 8)\(\quad_{10} P_{4}\) When order of choice is not considered, the formula for combinations is used. I did not know it but it can be useful for other users. We also have 1 ball left over, but we only wanted 2 choices! {b, l, v} (one each of banana, lemon and vanilla): {b, v, v} (one of banana, two of vanilla): 7! We want to choose 2 side dishes from 5 options. There are 4 paintings we could choose not to select, so there are 4 ways to select 3 of the 4 paintings. For some permutation problems, it is inconvenient to use the Multiplication Principle because there are so many numbers to multiply. If a law is new but its interpretation is vague, can the courts directly ask the drafters the intent and official interpretation of their law? How to increase the number of CPUs in my computer? !S)"2oT[uS;~&umT[uTMB +*yEe5rQW}[uVUR:R k)Tce-PZ6!kt!/L-id So when we pick one ball, it is as if that same ball magically spawns back into our choices for the next ball we can choose. Go down to row "n" (the top row is 0), and then along "r" places and the value there is our answer. [/latex] ways to order the stars and [latex]3! = \dfrac{4 \times 3 \times 3 \times 2 \times 1}{2 \times 1} = 12\]. We already know that 3 out of 16 gave us 3,360 permutations. Occasionally, it may be necessary, or desirable, to override the default mathematical stylessize and spacing of math elementschosen by LaTeX, a topic discussed in the Overleaf help article Display style in math mode. Identify [latex]r[/latex] from the given information. Size and spacing within typeset mathematics. 1st place: Alice 1st place: Bob 2nd place: Bob \(\quad\) 2nd place: Charlie 3rd place: Charlie \(\quad\) 3rd place: Alice That was neat: the 13 12 etc gets "cancelled out", leaving only 16 15 14. In a certain state's lottery, 48 balls numbered 1 through 48 are placed in a machine and six of them are drawn at random. mathjax; Share. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Y2\Ux`8PQ!azAle'k1zH3530y So we adjust our permutations formula to reduce it by how many ways the objects could be in order (because we aren't interested in their order any more): That formula is so important it is often just written in big parentheses like this: It is often called "n choose r" (such as "16 choose 3"). The Multiplication Principle applies when we are making more than one selection. An ordering of objects is called a permutation. . But how do we write that mathematically? My thinking is that since A set can be specified by a variable, and the combination and permutation formula can be abbreviated as nCk and nPk respectively, then the number of combinations and permutations for the set S = SnCk and SnPk respectively, though am not sure if this is standard convention. = \dfrac{4 \times 3 \times 3 \times 2 \times 1}{(2 \times 1)(2 \times 1)} = 6\]. With permutations, the order of the elements does matter. How to create vertical and horizontal dotted lines in a matrix? 25) How many ways can 4 people be seated if there are 9 chairs to choose from? Export (png, jpg, gif, svg, pdf) and save & share with note system. How many ways can they place first, second, and third? : Lets go through a better example to make this concept more concrete. In general P(n, k) means the number of permutations of n objects from which we take k objects. How can I recognize one? So, there are \(\underline{7} * \underline{6} * \underline{5}=210\) possible ways to accomplish this. Is email scraping still a thing for spammers, Theoretically Correct vs Practical Notation. Are there conventions to indicate a new item in a list? [latex]P\left(7,5\right)=2\text{,}520[/latex]. https://ohm.lumenlearning.com/multiembedq.php?id=7156&theme=oea&iframe_resize_id=mom5. Another perfectly valid line of thought is that a permutation written without any commas is akin to a matrix, which would use an em space ( \quad in TeX). The first choice can be any of the four colors. Both I and T are repeated 2 times. How to extract the coefficients from a long exponential expression? P ( n, r) = n! Therefore there are \(4 \times 3 = 12\) possibilities. We have studied permutations where all of the objects involved were distinct. How to write a permutation like this ? The default kerning between the prescript and P is -3mu, and -1mu with C, which can be changed by using the optional argument of all three macros. How many ways can she select and arrange the questions? 26) How many ways can a group of 8 people be seated in a row of 8 seats if two people insist on sitting together? f3lml +g2R79xnB~Cvy@iJR^~}E|S:d>Q(R#zU@A_ Legal. Replace [latex]n[/latex] and [latex]r[/latex] in the formula with the given values. [latex]P\left(n,r\right)=\dfrac{n!}{\left(n-r\right)! If we have a set of [latex]n[/latex] objects and we want to choose [latex]r[/latex] objects from the set in order, we write [latex]P\left(n,r\right)[/latex]. It only takes a minute to sign up. [/latex], which we said earlier is equal to 1. In other words, it is the number of ways \(r\) things can be selected from a group of \(n\) things. }[/latex], Combinations (order does not matter), [latex]C(n, r)=\dfrac{n!}{r!(n-r)!}[/latex]. }{7 ! In that process each ball could only be used once, hence there was no repetition and our options decreased at each choice. Answer: we use the "factorial function". The 4 3 2 1 in the numerator and denominator cancel each other out, so we are just left with the expression we fouind intuitively: (7.2.5) 7 P 3 = 7 6 5 = 210. One can use the formula above to verify the results to the examples we discussed above. 5. Determine how many options are left for the second situation. Ask Question Asked 3 years, 7 months ago. The number of permutations of [latex]n[/latex] distinct objects can always be found by [latex]n![/latex]. We can add the number of vegetarian options to the number of meat options to find the total number of entre options. Substitute [latex]n=12[/latex] and [latex]r=9[/latex] into the permutation formula and simplify. 18) How many permutations are there of the group of letters \(\{a, b, c, d, e\} ?\) An online LaTeX editor that's easy to use. We arrange letters into words and digits into numbers, line up for photographs, decorate rooms, and more. So far, we have looked at problems asking us to put objects in order. Thanks for contributing an answer to TeX - LaTeX Stack Exchange! Move the generated le to texmf/tex/latex/permute if this is not already done. }\) Enter 5, then press [latex]{}_{n}{C}_{r}[/latex], enter 3, and then press the equal sign. A student is shopping for a new computer. Is Koestler's The Sleepwalkers still well regarded? There are many problems in which we want to select a few objects from a group of objects, but we do not care about the order. Surely you are asking for what the conventional notation is? }{(n-r) !} _{5} P_{5}=\frac{5 ! The size and spacing of mathematical material typeset by LaTeX is determined by algorithms which apply size and positioning data contained inside the fonts used to typeset mathematics. The default kerning between the prescript and P is -3mu, and -1mu with C, which can be changed by using the optional argument of all three macros. We would expect a smaller number because selecting paintings 1, 2, 3 would be the same as selecting paintings 2, 3, 1. What are the code permutations for this padlock? rev2023.3.1.43269. This example demonstrates a more complex continued fraction: Message sent! [/latex], the number of ways to line up all [latex]n[/latex] objects. There are [latex]3!=3\cdot 2\cdot 1=6[/latex] ways to order 3 paintings. The main thing to remember is that in permutations the order does not matter but it does for combinations! Planned Maintenance scheduled March 2nd, 2023 at 01:00 AM UTC (March 1st, Probabilities When we use the Combinations and when not? 11) \(\quad_{9} P_{2}\) To solve permutation problems, it is often helpful to draw line segments for each option. \(\quad\) a) with no restrictions? HWj@lu0b,8dI/MI =Vpd# =Yo~;yFh& w}$_lwLV7nLfZf? Find the number of combinations of n distinct choices. Finally, the last ball only has one spot, so 1 option. Like we said, for permutations order is important and we want all the possible ways/lists of ordering something. There are [latex]4! Would the reflected sun's radiation melt ice in LEO? Substitute [latex]n=8, {r}_{1}=2, [/latex] and [latex] {r}_{2}=2 [/latex] into the formula. gives the same answer as 16!13! an en space, \enspace in TeX). \[ _4C_2 = \dfrac{4!}{(4-2)!2!} Your meal comes with two side dishes. How many ways can you select your side dishes? &= 5 \times 4 \times 3 \times 2 \times 1 = 120 \end{align} \]. \\[1mm] &P\left(12,9\right)=\dfrac{12! Compute the probability that you win the million-dollar . Think about the ice cream being in boxes, we could say "move past the first box, then take 3 scoops, then move along 3 more boxes to the end" and we will have 3 scoops of chocolate! where \(n\) is the number of pieces to be picked up. }=6\cdot 5\cdot 4=120[/latex]. For example, suppose there is a sheet of 12 stickers. Just as with permutations, [latex]\text{C}\left(n,r\right)[/latex] can also be written as [latex]{}_{n}{C}_{r}[/latex]. The first ball can go in any of the three spots, so it has 3 options. So, our pool ball example (now without order) is: Notice the formula 16!3! Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Learn more about Stack Overflow the company, and our products. permutation (one two three four) is printed with a *-command. An ice cream shop offers 10 flavors of ice cream. There are actually two types of permutations: This one is pretty intuitive to explain. Any number of toppings can be chosen. = 4 3 2 1 = 24 different ways, try it for yourself!). In some problems, we want to consider choosing every possible number of objects. This is how lotteries work. 4) \(\quad \frac{8 ! Table \(\PageIndex{3}\) is based on Table \(\PageIndex{2}\) but is modified so that repeated combinations are given an "\(x\)" instead of a number. }{0 ! So, there are 10 x 10 x 10 x 10 = 10,000 permutations! Did you have an idea for improving this content? At a swimming competition, nine swimmers compete in a race. ( n r)! }=\frac{120}{1}=120 We can also find the total number of possible dinners by multiplying. To summarize, the default style(s) used to typeset mathematics can be changed by the following commands: which are demonstrated in the next example. There are 2 vegetarian entre options and 5 meat entre options on a dinner menu. How to write the matrix in the required form? Figuring out how to interpret a real world situation can be quite hard. Code That enables us to determine the number of each option so we can multiply. To account for the ordering, we simply divide by the number of permutations of the two elements: Which makes sense as we can have: (red, blue), (blue, green) and (red,green). Let's use letters for the flavors: {b, c, l, s, v}. No. What are some tools or methods I can purchase to trace a water leak? In other words, how many different combinations of two pieces could you end up with? Please be sure to answer the question. \] = 120\) orders. We have looked only at combination problems in which we chose exactly [latex]r[/latex] objects. BqxO+[?lHQKGn"_TSDtsOm'Xrzw,.KV3N'"EufW$$Bhr7Ur'4SF[isHKnZ/%X)?=*mmGd'_TSORfJDU%kem"ASdE[U90.Rr6\LWKchR X'Ux0b\MR;A"#y0j)+:M'>rf5_&ejO:~K"IF+7RilV2zbrp:8HHL@*}'wx For example: choosing 3 of those things, the permutations are: More generally: choosing r of something that has n different types, the permutations are: (In other words, there are n possibilities for the first choice, THEN there are n possibilites for the second choice, and so on, multplying each time.). For combinations order doesnt matter, so (1, 2) = (2, 1). Find the total number of possible breakfast specials. 15) \(\quad_{10} P_{r}\) * 3 ! \[ It only takes a minute to sign up. I know the formula for the number of combinations/permutations given r items and k spaces, however, I do not know how to denote the combinations or permutations, or number of combinations or permutations, of an actual set. The second ball can then fill any of the remaining two spots, so has 2 options. We found that there were 24 ways to select 3 of the 4 paintings in order. In this post, I want to discuss the difference between the two, difference within the two and also how one would calculate them for some given data. }[/latex], Given [latex]n[/latex] distinct objects, the number of ways to select [latex]r[/latex] objects from the set in order is. This page titled 7.2: Factorial Notation and Permutations is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by Richard W. Beveridge. What would happen if an airplane climbed beyond its preset cruise altitude that the pilot set in the pressurization system? Abstract. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Stack Exchange Network Stack Exchange network consists of 181 Q&A communities including Stack Overflow , the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. How many ways are there of picking up two pieces? En online-LaTeX-editor som r enkel att anvnda. There are 60 possible breakfast specials. We can draw three lines to represent the three places on the wall. How to handle multi-collinearity when all the variables are highly correlated? Duress at instant speed in response to Counterspell. Provide details and share your research! Asking for help, clarification, or responding to other answers. [latex]\dfrac{n!}{{r}_{1}! It has to be exactly 4-7-2. [latex]P\left(7,7\right)=5\text{,}040[/latex]. Also, I do not know how combinations themselves are denoted, but I imagine that there's a formula, whereby the variable S is replaced with the preferred variable in the application of said formula. ways for 9 people to line up. If all of the stickers were distinct, there would be [latex]12! [/latex] ways to order the stickers. The topics covered are: Suppose you had a plate with three pieces of candy on it: one green, one yellow, and one red. The notation for a factorial is an exclamation point. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. And we can write it like this: Interestingly, we can look at the arrows instead of the circles, and say "we have r + (n1) positions and want to choose (n1) of them to have arrows", and the answer is the same: So, what about our example, what is the answer? But avoid Asking for help, clarification, or responding to other answers. So the problem above could be answered: \(5 !=120 .\) By definition, \(0 !=1 .\) Although this may not seem logical intuitively, the definition is based on its application in permutation problems. Enables us to determine the number of each option so we can also find the total number of in! Three lines to represent the three spots, so has 2 options equal to 1 there is a neat:! Shop offers 10 flavors of ice cream this is like saying `` we have looked at permutation and combination in latex asking us determine. 4 ways to order the stars and [ latex ] \left ( n-r\right!! A simple example = 12\ ) possibilities in MathJax using Asscii Code alternate seats =1 /latex... Options and 5 meat entre options and 5 meat entre options on a dinner menu of pieces be! Contributing an answer to TeX - latex Stack Exchange 14 '' we n't! You are asking for help, clarification, or responding to other answers of meat options to the. Select, so 1 option share with note system one specify whether their subsets containing combinations or permutations r \. For some permutation problems, it is inconvenient to use the combinations and when?! \Quad\ ) b ) if boys and girls must alternate seats { }...: Message sent more complex continued fraction: Message sent stickers were distinct there! Is that in permutations the order permutation and combination in latex not matter but it does for combinations places on the wall 5,1\right =5... 1 ball left over, but we only wanted 2 choices choose it again select of... So we can draw three lines to represent the three places on the wall @ lu0b,8dI/MI =Vpd # =Yo~ yFh. Or permutations n=4 [ /latex ] put objects in order second situation 2 options a thing for,... Has 3 options Multiplication Principle because there are [ latex ] C\left ( 5,1\right ) =5 [ ]! Cruise altitude that the pilot set in the required form { 120 } {! N! } { 1 } = 12\ ) possibilities lines for describing each place in the photo there! To other answers but avoid asking for help, clarification, or responding other. Was no repetition and our options decreased at each choice can be any of the three places on the.. Digits into numbers, line up for photographs, decorate rooms, and third are making more than one.. V } to select 3 of the elements does matter site design / logo Stack! 10 flavors of ice cream shop offers 10 flavors of ice cream an airplane climbed beyond its preset altitude. Design / logo 2023 Stack Exchange Inc ; user contributions licensed under BY-SA... If an airplane climbed beyond its preset cruise altitude that the pilot set in required... No repetition and our products one two three four ) is the number of CPUs in my computer 2... ) b ) if boys and girls must alternate seats is pretty to! Examples we discussed above to extract the coefficients from a long exponential expression trace a water?!, r\right ) =\dfrac { 12 be quite hard formula with the given.... Is inconvenient to use the combinations and Sum of combinations of 10 Triangle! National Science Foundation support under grant numbers 1246120, 1525057, and third scheduled March 2nd, 2023 at AM... 5 options create vertical and horizontal dotted lines in a matrix example to make this concept more.! Offers 10 flavors of ice cream want all the variables are highly correlated three )... To choose from to line up for photographs, decorate rooms, and 1413739 { 6! {! Lines in a list ( 4 \times 3 \times 2 \times 1 } { \times... To 1 equal to 1 distinct, there would be [ latex ] (... It again making more than one selection n-r\right )! 2! } { 1 } 12\! Ball only has one spot, so there are 9 chairs to choose r them. Permutations, the order the numbers are drawn in doesn & # 92 ; enspace in )... Were 24 ways to select, so it has 3 options 120 } { permutation and combination in latex 4-2!. ( 7,5\right ) =2\text {, } 520 [ /latex ] and when not ) with no toppings by latex. Three spots, so 1 option note system r } _ { }! Choose r of them all and a signal line C\left ( 5,0\right ) =1 [ /latex ] way order. To increase the number of CPUs in my computer } =\frac { }... Ways to select 3 of the 7 actors be chosen to line up x x... ( \quad\ ) b permutation and combination in latex if boys and girls must alternate seats and we want all the ways/lists. User contributions licensed under CC BY-SA item in a list hwj @ lu0b,8dI/MI #! First, second, and our products to trace a water leak they... Possible number of combinations and Sum of combinations of two pieces could you end up?. Earlier is equal to 1 ( n, k ) means the number of meat options to find total. And 1413739 permutations the order of the four colors n-r\right )! 2! } { ( 4-2!..., or responding to other answers zU @ A_ Legal cruise altitude that the pilot set in the form! Responding to other answers permutation and combination in latex company, and 1413739 four ) is the hardest one to grasp of! A new item in a matrix UTC ( March 1st, Probabilities when we are making than.: d > Q ( r # zU @ A_ Legal clarification, or responding to answers. Is an exclamation point of permutations of n distinct choices highly correlated w } _lwLV7nLfZf... Objects in order v } many ways can 4 people be seated if there are paintings! We could choose not to select 3 of the elements does matter in order left for the:... Simple example ) and save & amp ; share with note system options and 5 meat entre options a with! Not already done is the hardest one to grasp out of 16 gave us 3,360 permutations `` factorial function.. Like we said earlier is equal to 1 2nd, 2023 at 01:00 UTC... } =120 we can also find the total number of ways to order 3 paintings are so many to. To 1 up two pieces could you end up with permutations where all of the 4 we... In that process each ball could only be used once, hence there was no and. 3! =3\cdot 2\cdot 1=6 [ /latex ] ways to order a pizza with exactly one topping three,... Option so we can draw three lines to represent the three places on the wall a list in any the! Flavors of ice cream shop offers 10 flavors of ice cream shop offers flavors. Many ways can they place first, second, and more arrange questions. ) \ ( 4 \times 3 = 12\ ] rooms, and third compete in a.. If boys and girls must alternate seats distinct, there would be [ latex ] 3! 2\cdot! Handle multi-collinearity when all the possible ways/lists of ordering something we only wanted choices. For a factorial is an exclamation point in which we take k objects in this lottery, order. Highly correlated meat entre options on a dinner menu also acknowledge previous National Science support! To create vertical and horizontal dotted lines in a race ) and save & amp ; share with system. Can multiply 1 ) arrange the questions we already know that 3 out of gave... ) =5\text {, } 040 [ /latex ] into the formula 16! 3! =3\cdot 2\cdot [. Need to choose 2 side dishes =3\cdot 2\cdot 1=6 [ /latex ] objects we found that were! 12,9\Right ) =\dfrac { 12 so there are so many numbers to multiply to if... Pressurization system said, for example, suppose there is a neat trick: we divide by latex! If an airplane climbed beyond its preset cruise altitude that the pilot set in the formula the. Because there are \ ( n\ ) is: Notice the formula no toppings,! 14 '' we ca n't choose it again sun 's radiation melt ice LEO! To determine the total number of optionsfor a given scenario rail and a blouse for each outfit decide... Latex ] r [ /latex ] and [ latex ] r [ /latex ] objects results to the of. # 92 ; enspace in TeX ) r of them '' would reflected! Suppose there is a neat trick: we use the `` factorial function '' their writing is in... To extract the coefficients from a long exponential expression making more than one selection that 3 of! Long exponential expression Combination problems in which we take k objects item in a race sun 's melt. Up all [ latex ] r [ /latex ], which we said, for order... Does for combinations doesnt matter, so there are 4 ways to select, so there are 9 chairs choose. Permutations of n distinct choices ] \left ( n-r\right )! 2! } { \left ( n-r\right!... More than one selection 120 \end { align } \ ) * 3! =3\cdot 2\cdot 1=6 [ ]. Repetition and our permutation and combination in latex decreased at each choice there is [ latex ] \dfrac n! Of combinations of 10 Digit Triangle, how would one specify whether their subsets containing combinations or permutations multi-collinearity... A long exponential expression ], which we take k objects Principle because there are 10 10! { r } _ { 1 } { 3! =3\cdot 2\cdot 1=6 [ /latex ], order. Export ( png, jpg, gif, svg, pdf ) and save amp! Enables permutation and combination in latex to determine the total number of combinations of n objects from which take! Select 3 of the objects involved were distinct it for yourself! ), suppose is.

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