Odd Result With Boolean Union

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  • In mathematics and mathematical logic, Boolean algebra is the branch of algebra in which the values of the variables are the truth values true and false, usually denoted 1 and 0 respectively.

Boolean logic (also called Boolean algebra) is a complete system for logical operations, used often since popularization of mathematical logic and discussions concerning the foundations of mathematics.

Overview: Unlocking the mystéries of Boolean functions: How and why they function, why they fail, how to fix complications and make them function more regularly, knowing how they work on open items. Boolean functions can be great time saving techniques for developing items in Rhinó. But, for thé newbie, they appear to frequently mysteriously fail, and it is certainly challenging to know why. Ideally this Common questions explanation will clarify stuff a little bit. If you put on't would like to wade thróugh all the following info, you can furthermore try Mark Brock's i9000 short. To realize why Booleans fail, very first you must know how they function.

They are not really a miraculous tool for placing objects collectively. They are usually simply semi-automatic operations that combine several regular commands into one process.

The Boolean operations basically perform four things:. Join everything back again jointly Everything you can do with Boolean procedures you can also do manually by using the above four instructions. Using a Boolean procedure only speeds points up by making it one procedure -- when it functions So, the 1st factor to maintain in thoughts is certainly that a solid knowing of how the component functions of Booleans work is necessary. When all else falters, you can get the work carried out with these commands: Intersect, Split, Delete, and Join. Test undoing a profitable Boolean operation and redoing it manually using those instructions.

Get comfortable with the fact that this process will continually get you where you wish to move actually if your Boolean efforts fall short. Boolean operation failed. OK, why perform Booleans fall short? First, it is usually the intersection procedure that will determine the achievement or failing of a Boolean operation. If a right intersection is discovered, the rest is easy. But if Rhino provides problems obtaining the intersection, the Boolean procedure is assured to fail.

So the essential is to assist Rhino discover a good and full intersection. You can perform this by setting up your design and document correctly, and also by knowing some of Rhino's i9000 quirks and limitations. Intersecting two shut (strong) objects should produce at least one completely shut intersection shape (i.at the. It's possible there may be more than one loop if the object intersects in multiple areas -- no problem if they're also all closed. If actually one is open, nevertheless, the Boolean procedure will fail. This can be because the intersection contour does not completely reduce through the items. Rhino doesn't understand how to complete the slice, so it halts and gives you an mistake message.

Notice: Doing Boolean procedures on open up objects is also achievable, but a bit more complex, so we'll presume at first that all objects are shut. Open items will end up being covered afterwards. So, having the over into accounts, if your Boolean operation falters, the initial issue you should do is check out the intersection of the objects. Select your items and call Intersect.

First, look at each intersection curve on the display screen. Will it appear correct? Are usually generally there any visible spaces or additional sections or some other points that look unusual? If so, find out why. lf the intersection looks Fine, but the Boolean nevertheless fails while the intersection curve is still selected, proceed into Qualities >Information or use the order What. The ensuing info package should tell you all you require to know about the contour.

Does it say the contour is open? After that thats your issue area. More than one curve? You need to find out why there are usually either gaps or overIaps in your intérsection. Intersection difficulties, solutions, and limitations.

What causes spaces or issues in your intersection? There are many opportunities. Some are due to modeling errors or inaccuracies. Some are due to Rhino's i9000 limitations.

Allow's appear at the common errors first: If you believe your intersection should be shut, but it's not, select the competition, and call CrvStart, which spots a stage at the start of the competition. Usually this will correspond with one side of the space. Zoom lens in carefully and discover if you can find the space on the display. Why is definitely generally there a difference there? Maybe you think that your objects are closed, but they're really not really.

The intersection may mix a space between surfaces, and that will trigger an open up competition. If you possess forced together your object using JoinEdge, that may furthermore happen, actually though the object says closed. The some other factor to verify is usually your modeling toIerances. If they are usually as well large, this may prevent the intersector functionality from obtaining a comprehensive intersection, even though all else can be well.

Attempt tightening your tolerances and operating the Boolean again. Once you get a full closed intersection, your procedure should function If you can't obtain Rhino to immediately produce a closed intersection competition, actually after you have got fixed your object the best you can, it may become period to go back to guide. Get the best intersection competition you can and try modifying it until you have a shut object. You may require to include or modify a section, perform some stage editing, take out overlapping sections, or something like that. Once you possess this contour, you can test cutting off your items independently. You require to explode your polysurfaces to trim with the intersection contour.

Trim out the components you wear't need and join all back again up. Identified Rhino restrictions. Coincident seams - All objects possess seams. Occasionally when the séams on two items are usually at precisely the same location, Rhino offers difficulty with the intersection. Answer: Either try out to proceed the seam, or consider shifting one item just a small, tiny bit (if you can without producing your model incorrect). Or try to do the operation by hand.

Coplanar encounters. Very first, it can be necessary to recognize the concept of surface area normals and direction. Every surface object provides a “sided-ness”, that will be, a front side part and a backside.

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This is known as the direction in Rhino and can become shown with the Dir control. Try making use of Dir on many different areas and see what happens. The path arrows point to the outdoors of the surface, and they furthermore show the regional normal direction, i.y.

They are usually at 90º to the surface area locally. For each surface area, you can flip the direction of the normals (i actually.age. Invert the sidéd-ness of thé surface area. To do this, while you're in the Dir order, you either type F and enter, or just click once on the surface area. You will find the path arrows flip sidés. You can also do this outside the Dir command word by using the command word Switch (you will not find any arrows, though). Note: Figure in Rhino also have a direction which can become demonstrated by the Dir control.

In this situation, Flip trades the start and finish factors and reverses the contour direction. When areas are became a member of, Rhino tries to standardize the surface normals of the item. That is, it attempts to maintain all nearby surfaces getting the exact same entrance/back alignment. So when you possess an open place of joined up with areas (an open polysurface), it will still have got one uniform entrance/back and not really end up being a patchwork quilt of surfaces facing in different directions.

Experiment 1: Make a square. Extrude it intó a 4-sided open box. Increase it into split surfaces. Making use of Dir, change two of the areas' directions to the inside. Now screen go for them all and make use of Join to make them into á 4-sided polysurface again and make use of Dir once again to find what occurred to the surface area instructions.

When an object is shut in Rhino, the system instantly flips all the areas to the outdoors. It assumes we put on't treatment about the inside of anymore, because the object is shut (solid). Shut polysurfaces cannot possess their normals facing inside (try out to observe if you cán with Dir). lf you do take care of to flip the normals of a shut polysurface to the inside, either it isn't really closed, or, you have found out a (very rare) bug. Alright, today you know surface normals and direction. Why can be this essential in Boolean procedures? When Rhino can be instructed to perform a Boolean operation, it appears at the surface area normals to determine which components to maintain and which components to toss away.

Essentially, Boolean Association, Distinction, and Intersection are usually all the exact same operation. Just different parts of the items are held at the end. With Boolean Marriage, for instance, the parts that overlap are thrown aside and the relaxation joined jointly. With Intersect, it is definitely exactly the opposing. Booleans with solids (shut polysurfaces) are expected, because all surface area normals always stage to the outside.

But with open up polysurfaces the outcomes can seem unstable, as we don't instantly understand which is definitely the front or back again of each item without using the command Dir. Tip: One way to usually understand which method surfaces are usually facing is definitely to arranged up your display to display backfaces in a various colour from front side faces. In V3, use the command AdvancedDisplay>Color Backfaces to fixed this up. In V4, go to Options>Appearance>Advanced Settings>Shaded>Backface Configurations. In Sixth is v5, it's Options>View>Display Settings>Shaded>Backface Configurations. Then select Set single colour for all backfaces, and select a colour.

Take note, this just works if you are usually operating in Shaded Viewport setting. In Wireframe, Ghosted, or Delivered you will not see this. Let's visualize the simplest open up Boolean operation. You have one solid closed polysurface that can be completely intersected by a single surface area. Php ide for mac.

You can conveniently develop this by making any kind of solid object, then using the CutPlane order and drawing a cut range through your object in any path. Now, try out BooleanDifference (BD). Choose the strong as the very first set and the trim plane as the 2nd. One part or the some other of the strong will be reduce off and the gap loaded by the aircraft. But which aspect??? You can't understand unless you call Dir on the surface area. Appear at the path of the surface area normal.

Then perform your difference. Undo, switch the direction of the surface making use of Dir, then try the difference again. The path of the surface normal of the airplane determines which item gets still left. In common, if you need to BD between an open (poly) surface area and a solid to work as if it has been two solids, the surface area normals of the open object should point towards the solid item, as if it were also a strong. From Rhino V4 on, enables you cycle through all the opportunities of the various Boolean procedures and discover the result ón-screen.

You cán after that select the result you wish. Presently, this only functions with simply two objects.

How to use SQL Union in Collection Operations In this puzzle, we're heading to understand how to compose a SQL Association without using Set Operations. Set operations allow us to compare rows from two or even more tables to arrive at a result. For various classes of troubles, it will be much much easier to make use of a place procedure, than join information. But can we do without a SQL Marriage? Yet a great method to understand and recognize SQL will be to explore alternative strategies. Today we'll get rid of the SQL UNION operator out the door, and seek an option method to get there at the exact same result.

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Are usually you upward to the challenge? Solving puzzles will be a excellent way to find out SQL.

Nothing at all beats training what you've discovered. As soon as you have figured out the puzzle, blog post you response in the responses so we all can understand from one another. We also discuss a bit and even more in on Facebook. End up being sure to discover us there! SQL Union Two Results Using No Association Given two listings of numbers: A new and W Select just about all odd numbers ordered from highest tó lowest into á one result using one declaration WITHOUT Using any SET Operators like as UNION, EXCEPT, or INTERSECT. Right here is usually to create the desks.

Solution: Right here is the alternative I came up with today: WITH cteNumber (Quantity) AS ( SELECT ISNULL(A.Number, N.Quantity) FROM @A A Total OUTER JOIN @C B ON A new.Number = B.Quantity ) SELECT Amount FROM cteNumber WHERE Amount% 2 = 1 ORDER BY Amount DESC There are several components I'll move over; however, let's begin with the one that actually makes this mark - the. A Total OUTER Sign up for includes a LEFT and Ideal OUTER JOIN into one operation. This permit us to return every line from both furniture.

Where the join problem isn'capital t met, are returned. Here is definitely an instance: SELECT A new.Number ANumber, M.Amount BNumber FROM @A A FULL OUTER Sign up for @C W ON A new.Quantity = B.Amount And the outcomes demonstrated rows exceptional to their particular table, simply because nicely as those in common. If you look carefully, you'll find that we possess the beginnings of an Partnership procedure. All that we need to do is definitely “combine” the ANumbér and BNumber line values collectively for each line.

Perform to this we make use of the. The function ISNULL( worth, replacementValue) comes back a worth, and if worth Is definitely NULL, then replacementValue. Thus, ISNULL(ANumber, BNumber) comes back ANumber, and if ANumber Is usually NULL, then BNumber. Provided this, we can improve our issue to: SELECT ISNULL(A.Amount, B.Number) FROM @A A FULL OUTER Sign up for @W B ON A.Quantity = B.Number Which today returns the union of Amount for tables A and B. To complete the solution, I wrapped this Total OUTER Sign up for in a. After that, queried the results, examined for unusual quantities, and sorted in descending purchase. WITH cteNumber (Number) AS ( SELECT ISNULL(A.Quantity, B.Quantity) FROM @A A Total OUTER Sign up for @M M ON A.Quantity = B.Amount ) SELECT Quantity FROM cteNumber WHERE Amount% 2 = 1 Purchase BY Number DESC Keep in thoughts that% user comes back the modulo (remainder) of a department.

Any amount when divided by 2 whose rest can be 1, is usually odd. Also, to type number from highest to lowest, use the DESC (descending) qualifier. Here are usually the outcomes: Alternative Answer If you put on't like common table expressions, or your version of SQL doesn'testosterone levels support them, then you'll see this reply a little bit more traditional: SELECT ISNULL(A.Quantity, B.Amount) as Amount FROM @A A FULL OUTER JOIN @M T ON A new.Amount = B.Amount WHERE A.Number% 2 = 1 OR N.Quantity% 2 = 1 Purchase BY Quantity If you're like me, you're almost all likely looking at the WHERE clause and questioning why we're also making use of OR rather than AND.

At 1st I thought AND would end up being the method to go, after all we just wish to keep odd values from both furniture. Yet, once I thought about it, I noticed some of the columns return NULL, and NULL% 2 is certainly NULL, therefore making use of AND would limit any rows unique to one desk. I then believed about 0R.

With this BooIean user, we're ensuring we get the odd values, also if the some other columns is certainly NULL, and in the case both columns arén't null, théy are usually equal, expected to the sign up for operator, therefore OR in this case is Okay! Alright - So how would you resolve this problem? Place your response in the feedback!

For additional uses, notice. In and, Boolean algebra is the branch of in which the values of the are the accurate and fake, usually denoted 1 and 0 respectively. Instead of where the beliefs of the variables are figures, and the primary operations are inclusion and multiplication, the major functions of Boolean algebra are usually the and dénoted as ∧, the ór denoted as ∨, ánd the not really denoted as ¬. It is definitely hence a formalism for explaining logical relations in the exact same way that elementary algebra talks about numeric relations. Boolean algebra was released by in his 1st guide The Mathematical Analysis of Logic (1847), and fixed forth more completely in his (1854).

Relating to, the phrase 'Boolean algebra' had been first suggested by in 1913, although in 1880 offered the title 'A Boolian AIgebra with One Constant' to the very first part of his 'The Simplest Mathematics'. Boolean algebra offers been basic in the advancement of, and will be provided for in all contemporary programming languages. It will be also used in. Venn diagrams for association, disjunction, and suit For combination, the area inside both circles is tinted to reveal that times∧ y will be 1 when both factors are 1. The additional regions are remaining unshaded to show that times∧ con is definitely 0 for the various other three combos. The 2nd diagram symbolizes disjunction back button∨ y by covering those areas that lay inside either or both circles.

The third diagram represents go with ¬ a by shading the area not within the group. While we possess not demonstrated the Venn blueprints for the cónstants 0 and 1, they are trivial, being respectively a white box and a dark package, neither one made up of a group. Nevertheless we could put a group for back button in those boxes, in which case each would denote a function of one argument, a, which results the exact same value independently of a, called a constant function. As considerably as their outputs are concerned, constants and constant functions are usually indistinguishable; the difference is certainly that a constant takes no disputes, called a zeroary or nullary procedure, while a constant functionality will take one case, which it ignores, and can be a unary procedure. Venn layouts are useful in imagining laws.

The commutativity laws and regulations for ∧ and ∨ can end up being noticed from the symmetry of the diagrams: a binary procedure that had been not really commutative would not have got a symmetric diágram because interchanging back button and y would have the effect of highlighting the diagram horizontally and any failure of commutativity would after that appear as a failure of symmetry. Of ∧ and ∨ can end up being visualized by slipping the two sectors collectively and noting that the shaded area after that turns into the entire group, for both ∧ and ∨. To observe the very first absorption rules, x∧( back button∨ con) = times, start with the diágram in the middle for back button∨ y and note that the part of the in the shade region in common with the x circle is certainly the whole of the back button circle. For the 2nd absorption law, x∨( a∧ y) = back button, begin with the still left diagram for a∧ y and be aware that shading the entire of the a circle outcomes in just the x circle becoming shaded, since the previous shading was inside the back button group.

The dual negation legislation can be noticed by complementing the shading in the third diagram for ¬ back button, which shades the back button group. To visualize the very first Para Morgan'h legislation, (¬ a)∧(¬ con) = ¬( a∨ con), start with the middle diagram for back button∨ y and go with its shading so that only the region outside both sectors is shaded, which is usually what the correct hand aspect of the rules explains. The result is the exact same as if we tinted that region which can be both outside the back button group and outside the con circle, we.elizabeth. The association of their exteriors, which is definitely what the left hand part of the legislation explains. The second De Morgan's legislation, (¬ a)∨(¬ y) = ¬( a∧ con), works the same method with the two blueprints interchanged. The very first complement law, times∧¬ back button = 0, states that the interior and exterior of the x circle possess no overlap. The 2nd complement rules, x∨¬ x = 1, states that everything is certainly possibly inside or outside the x circle.

Digital logic entrance Digital logic can be the program of the BooIean algebra of 0 and 1 to electronic hardware consisting of connected to form a. Each gate deploys a Boolean procedure, and will be portrayed schematically by a shape suggesting the operation. The shapes related with the entrances for combination (AND-gates), disjunctión (OR-gates), ánd complement (inverters) are as follows. The ranges on the left of each gate represent input cables or slots. The worth of the input is symbolized by a voItage on the business lead. For so-called 'active-high' logic, 0 can be represented by a voltage close up to zero or 'terrain', while 1 can be represented by a voltage close to the offer voltage; active-Iow reverses this. Thé range on the ideal of each gate represents the result port, which usually follows the same voltage exhibitions as the insight ports.

Odd Result With Boolean Union Fail

Supplement is implemented with an inverter gate. The triangle denotes the operation that merely duplicates the insight to the output; the little circle on the result denotes the real inversion complementing the insight. The tradition of putting such a circle on any interface means that the sign passing through this slot is accompanied on the way through, whether it will be an insight or result port. The, or, can end up being comprehended as asserting that complementing all three slots of an AND door changes it to an OR door and vice versa, as demonstrated in Figure 4 below.

Complementing both ports of an inverter nevertheless leaves the operation unchanged. More usually one may enhance any of thé eight subsets óf the three ports of either an AND or OR door.

The resulting sixteen possibilities give rise to just eight Boolean functions, namely those with an unusual amount of 1'beds in their truth desk. There are usually eight like because the 'ódd-bit-out' cán be either 0 or 1 and can go in any of four roles in the reality desk. There being sixteen binary Boolean procedures, this must keep eight functions with an actually amount of 1'h in their truth desks. Two of these are the constants 0 and 1 (as binary procedures that ignore both their inputs); four are usually the operations that depend nontrivially on specifically one of their two inputs, namely times, y, ¬ times, and ¬ y; and the remaining two are usually x⊕ y (XOR) and its complement a≡ con.

Boolean algebras. Major content: and The above description of an summary Boolean algebra as a set and functions pleasing 'the' Boolean laws raises the question, what are those laws? A simple-minded reply is usually 'all Boolean laws and regulations,' which can be defined as all equations that hold for the BooIean algebra of 0 and 1. Since there are usually infinitely many such laws and regulations this will be not a terribly satisfactory answer in practice, major to the next query: will it be enough to require only finitely many laws and regulations to keep?

In the case of Boolean algebras the response can be yes. In particular the finitely many equations we have got shown above suffice. We state that Boolean algebra is definitely finitely axiomatizable or finitely structured. Can this listing be produced shorter yet?

Again the answer can be yes. To start with, some of the over laws are usually implied by some óf the othérs. A adequate subset of the above laws and regulations consists of the sets of associativity, commutativity, and assimilation laws, distributivity of ∧ ovér ∨ (or the various other distributivity law-one suffices), and the two complement laws. In reality this is definitely the conventional axiomatization of BooIean algebra as á. By introducing additional laws and regulations not listed above it gets to be probable to cut short the listing yet further. In 1933, demonstrated that if the fundamental operations are taken to end up being back button∨ con and ¬ x, with back button∧ y considered a derived operation (elizabeth.gary the gadget guy.

Via Para Morgan's regulation in the form back button∧ y = ¬(¬ a∨¬ y)), then the formula ¬(¬ a∨¬ y)∨¬(¬ back button∨ con) = x along with thé two equations conveying associativity and commutativity of ∨ completely axiomatized Boolean aIgebra. When the only basic operation is definitely the binary ¬( a∧ y), provides suggested in his reserve the individual rule ((( xy) z .)( x(( xz) x))) = z as á one-equation axiómatization of Boolean aIgebra, where for convénience here xy dénotes the NAND rathér than thé AND óf x and y. PropositionaI logic. Main post: is definitely a that will be intimately linked to Boolean algebra. Several syntactic principles of Boolean algebra carry over to propositional logic with just minor modifications in notation and terminology, while the sémantics of propositional logic are defined via Boolean aIgebras in a way that the tautologies (theorems) of propositional reasoning correspond to equationaI theorems of BooIean algebra. Syntactically, évery Boolean phrase corresponds to a of propositional reasoning. In this interpretation between Boolean aIgebra and propositional logic, Boolean factors x,y turn out to be (or atóms) P,Q, BooIean conditions like as back button∨ y turn out to be propositional formulas G∨ Queen, 0 becomes fake or ⊥, and 1 gets to be true or Testosterone levels.

It is certainly practical when mentioning to common propositions to use Greek words Φ, Ψ, as metavariables (variabIes outside the vocabulary of propositional calculus, utilized when talking about propositional calculus) to represent propositions. The sémantics of propositional reasoning rely on s i9000. The important concept of a truth assignment is definitely that the propositional factors are mapped to elements of a set Boolean algebra, and after that the of a propositional method using these letters is usually the component of the BooIean algebra that is definitely attained by processing the value of the Boolean phrase corresponding to the formulation. In traditional semantics, just the two-eIement Boolean algebra is definitely used, while in arbitrary Boolean algebras are usually regarded as. A is a propositional formula that is assigned reality worth 1 by every truth project of its propositional factors to an human judgements Boolean algebra (ór, equivalently, every reality project to the two element Boolean algebra). These semantics enable a interpretation between tautologies of propositional logic and equational théorems of Boolean aIgebra.

Every tautology Φ óf propositional logic can end up being indicated as the Boolean formula Φ = 1, which will be a theorem óf Boolean algebra. Alternatively every theorem Φ = Ψ of Boolean algebra corresponds to the tautologies (Φ∨¬Ψ) ∧ (¬Φ∨Ψ) and (Φ∧Ψ) ∨ (¬Φ∧¬Ψ). If → is definitely in the vocabulary these final tautologies can also be composed as (Φ→Ψ) ∧ (Ψ→Φ), or as two distinct theorems Φ→Ψ and Ψ→Φ; if ≡ will be available then the solitary tautology Φ ≡ Ψ can end up being used. Programs One motivating software of propositional calculus is the evaluation of propositions and deductive fights in natural language. Whereas the idea 'if times = 3 then x+1 = 4' is dependent on the meanings of like symbols as + and 1, the proposition 'if a = 3 then a = 3' will not; it can be true merely by virtue of its construction, and remains correct whether ' a = 3' is certainly replaced by ' a = 4' or 'the moon will be produced of natural mozzarella cheese.' The generic or abstract type of this tautology is 'if G then P', or in the language of Boolean algebra, ' G → P'. Replacing G by x = 3 or any additional proposition is usually called instantiation of P by that idea.

The result of instantiating P in an summary proposition will be called an instance of the idea. Thus ' back button = 3 → back button = 3' will be a tautology by virtue of getting an instance of the abstract tautology ' P → P'.

All situations of the instantiated variable must become instantiated with the exact same task, to avoid such nonsense as P → back button = 3 or a = 3 → times = 4. Propositional calculus limits attention to subjective propositions, those built up from propositional factors making use of Boolean functions. Instantiation is still achievable within propositional calculus, but only by instantiating propositional variables by abstract propositions, such as instantiating Queen by Queen→ G in G→( Q→ P) to yield the instance G→(( Queen→ G)→ G). (The accessibility of instantiation as part of the machinery of propositional calculus avoids the need for metavariables within the language of propositional calculus, since common propositional variables can end up being regarded as within the language to represent arbitrary propositions. The metavariables themselves are usually outside the reach of instantiation, not being component of the language of propositional calculus but rather component of the exact same vocabulary for talking about it that this phrase is created in, where we require to end up being able to differentiate propositional factors and their instantiations as getting specific syntactic entities.) Deductive systems for propositional reasoning An axiomatization óf propositional calculus is definitely a set of tautologies known as and one or even more inference rules for producing new tautologies from old.

A proof in an axiom system A is usually a finite nonempty series of propositions éach of which is usually either an instance of an rule of A or even comes after by some rule of A from propositions showing up previous in the evidence (therefore disallowing circular reasoning). The last proposition will be the theorem proved by the proof. Every nonempty preliminary segment of a evidence is certainly itself a evidence, whence every task in a proof is itself a théorem. An axiomatization is usually sound when every theorem is usually a tautology, and complete when every tautology is a theorem. Sequent calculus.

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