Friday, March 06, 2015

[zyxbhqnd] Defining monads with do notation

If one happens to be most comfortable with "do" notation for monads ("What are monads? They are the things for which "do" notation works well."), so monads implicitly being defined in terms of bind (>>=) and return, here are the definitions of map and join, the "other" way of defining monads:

join :: (Monad m) => m (m a) -> m a;
join xs = do { x <- xs ; x }

map :: (Monad m) => (a -> b) -> m a -> m b;
map f xs = do { x <- xs ; return $ f x }

map is identical to liftM and slightly narrower than fmap which requires only the Functor typeclass instead of Monad.  This redundancy is one of the motivations for the AMP proposal.  Incidentally, map (as defined above) would work as well as the famous Prelude map function which operates only on lists, because a list is a Monad (and a Functor).

Just for completeness, here is bind defined in do notation:

(>>=) xs f = do { x <- xs ; f x }

I sometimes like explicitly using the bind operator instead of do notation because the syntax, specifying xs then f, lines up well with the thought process "first prepare the input xs to a function, then call the function f on it".  It also works well for longer chains.  For example, the expression xs >>= f >>= g >>= h is equivalent to

do {
x <- xs;
y <- f x;
z <- g y;
h z;

but not having to name the intermediate results.

Inspired by the tutorial Monads as containers.

Wednesday, March 04, 2015

[etispurv] Multiply factors by hand

As the ceremonial final task of a large integer factorization project, multiply the discovered factors by hand.  How difficult is multiplying P143 and P177?  Consider making it a distributed task.

Tuesday, March 03, 2015

[mwrhkzem] Fields

TTANTS: Field's medal, Field's metal.

[znbyudna] Crypto user challenge

It is one challenge to design good cryptography.

It is yet another challenge to use the cryptography properly, avoiding mistakes.  This seems far more difficult.

Inspired by the difficulty of properly securing a private key but having it accessible to use.

[dklpneca] Multi freeze

Create a device that will repeatedly automatically freeze and thaw something.  For food, it might act like a blender, destroying cell walls at the microscopic level through ice crystals.  Tricky to know if something has thawed, or frozen, all the way through, so when to go to the next part of the cycle.

[emdoixka] 27 to 9

Base 9 is a convenient form factor for a physical input device: 9 buttons.  Base 27 might be a convenient coding of letters in the alphabet, though there are some tricky details.  Can a human learn to quickly convert a string from base 27 to base 9?

[bxbxpwcy] Sublight starship

At first, it seems like a typical sci-fi show with our heroes traveling among the stars in spaceships.  Then it is revealed they do not have faster-than-light transportation technology: their voyages actually take tremendous amounts of time.  The characters appear not to age because they have made huge improvements in longevity; they are all actually (say) thousands of years old.  That they have solved aging explains why these old characters are played by young, good-looking actors (of course).

Years might go by between scenes.  Completely elided is the monotony of the thousands of years in which nothing happens.

Thursday, February 26, 2015

[qufrnpys] Rocket science

How much of rocket science is classified for fear of our enemies using the knowledge to make missiles?

Given that the ultimate fate of humanity depends on us being able to get off this planet -- and the clock is ticking -- barriers to disseminating rocket science knowledge and thus delaying follow-up research might become the cause our own extinction.

Wednesday, February 25, 2015

[awvdtpmv] Female Superman

In a live action adaptation, e.g., movie, let an actress play an alien character previously depicted as male (or vice versa) in other media.  The idea is there is no logical reason for aliens to resemble human gender presentation.

This is not, say, Supergirl as a completely separate character from Superman, but the consistent Superman character with the same back story and mythology who simply looks different in live action compared to in a comic book.

I suspect for some, perhaps many, alien superhero characters, the audience will not find this too jarring because the character is defined by their abilities and not their gender presentation.

Inspired by Peter Pan typically played by a woman, and similarly Link played by a woman in freddiew's Zelda Pot Smasher.

[pgmfmvqq] Opening book battle

A battle of opening books on otherwise equal chess engines might be a way for humans to remain relevant in chess competition at the highest level.  The opening is where long term strategic decisions get made, supposedly a human strength over computers.

We need some mechanism to inject randomness, especially for a head to head match.  The opening book itself might give several equal moves.  Multi-threading in the engine might cause randomness.  Or the engine could be programmed to randomly choose between moves with the same evaluation.

We might also need a mechanism to handicap weaker engines, in case an opening book author prefers a weaker engine.  Easiest is probably to compute the opening book quality as a delta performance improvement over the engine's performance rating with its default book.  Otherwise, time advantage.

[lgxjbsjv] Non neutral wikipedia

There exist topics on Wikipedia in which a neutral point of view is difficult if not impossible.  This results in unending edit wars.

Resolve these disputes by technical means: allow a means for an article to be presented from multiple points of view, and the reader is notified that multiple exist and may select among them.  A vaguely similar mechanism already exists for choosing language.  (Inspired by articles with disputes over British or American spelling.)

We probably need tools to keep the articles as otherwise similar as possible for the non-disputed sections.

[blkensaf] Censorship resistant Wikipedia

Consider uploading the entirety of Wikipedia into a censorship resistant medium such as Freenet, then allowing it to be updated through that medium also, essentially forking it.

Although this will infuriate a lot of people, the first interesting new capability enabled by this will be the impossibility of removing copyrighted content.  Among other things, this means that the sources of an article can be mirrored and uploaded, too, which will be a tremendous benefit to researching via this forked Wikipedia.  This could be a killer app.  (Though there remains the difficulty of verifying that the mirrored copy of the source is accurate and has not been tampered with.)

Consider the large but not impossible task of preparing an initial upload consisting of all the articles and a copy of as many of the mirrored sources as obtainable within a reasonable budget, as a way of bootstrapping the project and getting others interested in contributing.

There remains the very difficult task of creating a community, of being able to resolve disputes and enforce rules in such a medium, to keep the content at high quality.  Wikipedia has a ban hammer, which might not be available on Freenet.

[jqcomdum] 3D density

Depict density in a 2D region by a height map in 3D, either a physical sculpture, probably 3D printed, or in virtual 3D.  This ends up making volume represent quantity (integral of density), which is nice.

Modify the density while preserving volume to avoid topographic basins, low density regions completely surrounded (and thus obscured if not looking from above) by higher density regions.  More generally, assume a light source that is limited to within a certain angle from horizontal.  Avoid permanently shadowed regions.

Inspired by a density map of the population.  The shades of gray do not have enough dynamic range.

Saturday, February 21, 2015

[lbjzxojd] Light distance and hertz

c/(1 GHz) = 30 cm
c/(1 cm) = 30 GHz

The clock speed at which design of microprocessors of 1cm size becomes very difficult due to clock skew. And the speed of electricity in microchips is slower than c.

[nblgfesi] Gryphon variations

The gryphon is a neat fairy chess piece functioning kind of like a fat rook.  Suppose a gryphon sits at (0,0).  The unmodified original piece can move to (1,n) where n>0, plus reflections.  Here are some possible variations of it:

Remove the constraint that (1,1) must be empty, giving it jumping ability like a knight.

Allow it to also move to (1,0).  This makes its attack area shaped like a hash symbol.

We can also imagine an analogous fat bishop.  It is not colorbound; in fact it alternates colors each move like a knight.

The crooked bishop is also somewhat like a fat rook, attacking not just the rank or file it is on, but also the adjacent files.  We could imagine a hybrid: a colorbound gryphon.  Several possibilities of, what squares must be empty to permit the colorbound gryphon to progress?  One possibility is it has crazy jumping ability, kind of like a nightrider, actually dabbaba-rider.

[xclwdqbq] Dabbabarider

The dabbaba rider is an elegant fairy chess piece when playing on checkerboard, unlike the alfil rider or nightrider.  The alternating square colors help easily distinguish where it can go and what it can jump over (but not where it can ultimately get to, due to its 4 way parity).

Add it to this list, so augmenting the number of possible Dabbaba abilities to 3 instead of 2: none, single jump, rider.  New total: 108 possibilities.

The dabbabarider bishop compound is nice, perhaps the most powerful colorbound piece (until we get to variations of fat pieces like the colorbound gryphon and crooked bishop).

We could also have a weaker dabbaba jumping ability in which it can only jump over empty squares, so equivalently a colorbound rook.

Orthogonal movement abilities, probably a lattice:
wazir < wazir rider (rook)
weak dabbaba < weak dabbaba rider
strong dabbaba < strong dabbaba rider
weak dabbaba < strong dabbaba
weak dabbaba rider < strong dabbaba rider
weak dabbaba rider < wazir rider

Exercise to count the possibilities. Somewhere between 9 and 64. Looks like 1 null, 6 noncompounds, 7 double compounds, and 1 triple compound (Wazir + Strong Dabbaba + Weak Dabbaba Rider) for a total of 15. The only colorbound compound is Strong Dabbaba + Weak Dabbaba Rider. Total piece possibilities is 180.

[dxdzeuyl] 7 fonts

Propose a standardized set of fonts to have specific meanings in written language.  Informal standards already exist: monospace is code, italic is foreign words.  Imagine, for example, sarcasm typeset in a different font.

Serif, Serif Bold
Serif Italic, Serif Italic Bold
Sans Serif, Sans Serif Bold

There remains the problem that certain letters, e.g., o e, look very similar between the fonts.

Another possibility is two fonts, one with horizontal strokes thickened and the other with vertical: a calligraphic pen in two orientations.  There is a problem of diagonal strokes looking similar, e.g., V, though this could be distinguished by different looking serifs. More radically, define characters that are designed to look different with the pen in the different orientations. The two 45 degree orientations might also be interesting.

Inspired by being nostalgic about the days of Antiqua and Fraktur, two very different fonts which could be both read by people with equal facility, allowing interesting typography by interspersing them.

[nxeqbztg] Fairy chess symbols

Represent on a diagram these 72 isotropic fairy chess pieces each with a different icon (text box) containing up to 5 characters.  For binary characteristics (various jumps), the presence or absence of a letter.  For ternary characteristics: a letter that looks different between uppercase (majuscule) and lowercase (minuscule) or absence.

Vaguely similar to Betza's Funny Notation.

Previously, constructing physical pieces for over the board play.  This time, we avoid color to not oppress the colorblind and to decrease the avoid the cost of printing diagrams in color.

White text on black background or vice versa depending on who owns the piece.  We need one more bit to designate the royal piece, perhaps decorate with a crown or cross.

If there were quaternary (or more) characteristics, we could add accents, choosing from letters without ascenders.

[xmotohqa] Spinning boiling hot dog

When boiling a floating single hot dog in a small uncovered skillet filled with water, the hot dog periodically flips itself about 180 degrees with a period of about 40 seconds.

Hypothesized mechanism: water trapped in the bottom of hot dog matrix boils, decreasing its density near the bottom. The hot dog flips, bringing that less dense portion to float slightly above the water level, where the vapor cools and condenses within the matrix.

[qmsvhwht] Trusting NSA cryptanalysis

We are in a curious situation in which if the NSA says something is insecure, we trust their advice, but if they say something is secure, we don't trust them.  Of course, this is because cryptanalysis results can be independently verified.

This does suggest a way for the NSA to regain public confidence, at least among cryptographers: publish more cutting edge cryptanalysis.  Does the NSA need more public confidence?  There is a political component to putting regulations in place for the government to secure its own secrets, one of the NSA's mandates (Information Assurance).

Much like the poisoned wine puzzle in The Princess Bride: the NSA could be saying to trust something (that they believe is secure) in hopes others don't trust them, so the others use insecure cryptography instead, which was the NSA's Signals Intelligence (surveillance) goal.  However, knowing that this might be the case, what should the others do?  Fun with game theory.