I will try to help with the title question. I think that the real motivation for the Levi-Civita connection comes from looking at surfaces in Euclidean 3-space. Differentate one tangent vector field Y along another X by first extending them to be defined in the ambient space, and then taking the tangential projection of XY, i.e. tangential projection of the Euclidean connection. Levi-Civita discovered that this process is intrinsic, i.e. invariant under isometry of surfaces without carrying along the ambient space, and described precisely by torsion freedom. This was clearly a long and difficult process. Dirac uses this view in his book General Theory of Relativity, and this is how I introduce the Levi-Civita connection in my lectures. I have to agree that there is something missing in the textbook discussions of torsion. I have not found an intuitive understanding of torsion.
aerc
: email client for CLIkaitai
is like 010
editor for drilling into binary formats, but also FOSS. With a web IDE!math.se
linkL
.stacker
monochrom
’s favourite work of djikstra: http://www.vex.net/~trebla/ewd.htmlIn situation X I will do behaviour Y to achieve subgoal Z Value affirmation: Remind yourself of the why.
Learning synths: https://learningsynths.ableton.com/en/making-changes/amplitude | https://news.ycombinator.com/item?id=20272346 |
Consider a set of opaque colored sheets, along with a binary operation of stacking sheets. Then every sheet is a left identity, UNLESS you add a transparent sheet to the set, at which point none of the other sheets are left identities anymore, and only the transparent sheet remains as an identity.
There are two views as to why people stay poor. The equal opportunity view emphasizesthat differences in individual traits like talent or motivation make the poor choose lowproductivity jobs. The poverty traps view emphasizes that access to opportunitiesdepends on initial wealth and hence poor people have no choice but to work in lowproductivity jobs. We test the two views using the random allocation of an asset transferprogram that gave some of the poorest women in Bangladesh access to the same jobopportunities as their wealthier counterparts in the same villages. The data rejectsthe null of equal opportunities. … Our findings imply that largeone-off transfers that enable people to take on more productive occupations can helpalleviate persistent poverty.
Nozick argues in favor of a minimal state, “limited to the narrow functions of protection against force, theft, fraud, enforcement of contracts, and so on.” When a state takes on more responsibilities than these, Nozick argues, rights will be violated. To support the idea of the minimal state, Nozick presents an argument that illustrates how the minimalist state arises naturally from anarchy and how any expansion of state power past this minimalist threshold is unjustified.
Z[x1,..., xn, e1, ... en]
where the ei
anticommute amongst themselves, and commute with the xi
.
This gives it a symplectic dimension (ei
), regular space dimension (xi
),
plus a single Z
dimension. This somehow leads to the notion that Spec(Z)
ought
to be thought of as a 3-manifold..Traditional Inuit parenting is incredibly nurturing and tender. If you took all the parenting styles around the world and ranked them by their gentleness, the Inuit approach would likely rank near the top. (They even have a special kiss for babies, where you put your nose against the cheek and sniff the skin.) The culture views scolding — or even speaking to children in an angry voice — as inappropriate, says Lisa Ipeelie, a radio producer and mom who grew up with 12 siblings. “When they’re little, it doesn’t help to raise your voice,” she says. “It will just make your own heart rate go up.” Traditionally, the Inuit saw yelling at a small child as demeaning. It’s as if the adult is having a tantrum; it’s basically stooping to the level of the child, Briggs documented.
Spec
where Spec
is drawn as “layered” instead of “fuzzy” as mumford does.The drama triangle is a social model of human interaction – the triangle maps a type of destructive interaction that can occur between people in conflict The triangle of actors in the drama are oppressors, victims and rescuers. The Victim: The Victim’s stance is “Poor me!” The Victim feels victimized, oppressed, helpless, hopeless, powerless, ashamed, and seems unable to make decisions, solve problems, take pleasure in life, or achieve insight. The Victim, if not being persecuted, will seek out a Persecutor and also a Rescuer who will save the day but also perpetuate the Victim’s negative feelings. The Rescuer: The rescuer’s line is “Let me help you.” A classic enabler, the Rescuer feels guilty if they don’t go to the rescue. Yet their rescuing has negative effects: It keeps the Victim dependent and gives the Victim permission to fail. The rewards derived from this rescue role are that the focus is taken off of the rescuer. When they focus their energy on someone else, it enables them to ignore their own anxiety and issues. This rescue role is also pivotal because their actual primary interest is really an avoidance of their own problems disguised as concern for the victim’s needs. The Persecutor: (a.k.a. Villain): The Persecutor insists, “It’s all your fault.” The Persecutor is controlling, blaming, critical, oppressive, angry, authoritarian, rigid, and superior.
Most of it is readable to undergraduates. Its target audience, though, is beginning graduate students in mathematics. If not already familiar with hyperbolic geometry, you might want to get an introduction to the subject first. Once with this background, though, you will discover there is another level of understanding of hyperbolic space you never realized was possible. One imagines Thurston able to skateboard around hyperbolic space with the kind of geometric understanding he conveys here.
What both Russell and Conrad were getting at was a simple fact which any historian could confirm: human civilisation is an intensely fragile construction. It is built on little more than belief: belief in the rightness of its values; belief in the strength of its system of law and order; belief in its currency; above all, perhaps, belief in its future. … Once that belief begins to crumble, the collapse of a civilisation may become unstoppable. That civilisations fall, sooner or later, is as much a law of history as gravity is a law of physics. What remains after the fall is a wild mixture of cultural debris, confused and angry people whose certainties have betrayed them, and those forces which were always there, deeper than the foundations of the city walls: the desire to survive and the desire for meaning … What remains after the fall is a wild mixture of cultural debris, confused and angry people whose certainties have betrayed them, and those forces which were always there, deeper than the foundations of the city walls: the desire to survive and the desire for meaning
“Many students, especially those who are poor, intuitively know what the schools do for them. They school them to confuse process and substance. Once these become blurred, a new logic is assumed: the more treatment there is, the better are the results; or, escalation leads to success. The pupil is thereby “schooled” to confuse teaching with learning, grade advancement with education, a diploma with competence, and fluency with the ability to say something new. His imagination is “schooled” to accept service in place of value. Medical treatment is mistaken for health care, social work for the improvement of community life, police protection for safety, military poise for national security, the rat race for productive work. Health, learning, dignity, independence, and creative endeavor are defined as little more than the performance of the institutions which claim to serve these ends, and their improvement is made to depend on allocating more resources to the management of hospitals, schools, and other agencies in question. In these essays, I will show that the institutionalization of values leads inevitably to physical pollution, social polarization, and psychological impotence: three dimensions in a process of global degradation and modernized misery.”
Radical monopoly is a concept defined by philosopher and author Ivan Illich in his 1973 book, “Tools for Conviviality,” and revisited in his later work, which describes how a technology or service becomes so exceptionally dominant that even with multiple providers, its users are excluded from society without access to the product. His initial example is the effect of cars on societies, where the car itself shaped cities by its needs, so much so that people without cars become excluded from participation in cities. A radical monopoly is when the dominance of one type of product supersedes dominance by any one brand. Social media as a technology in the forms of Facebook/Instagram/Twitter could be seen as a radical monopoly for reputation, as is Linkedin for employment, colleges for education, etc. I think Illich’s criticisms of car culture pushed him outside the Overton window of policy making, but his radical monopoly concept is a useful critical tool for reasoning about tech and ethics. A counter argument could use the example that the discovery of fire created a radical monopoly on heat, and therefore it’s so general as to be applied arbitrarily to anything you don’t like. However, being able to think about the consequences of a new radical monopoly might have on some aspect of human experience is useful for anticipating policy options in response to dynamic technology development.
It sounds like the issue is that the layout isn’t spatial. There isn’t a 1:1 mapping between place and object. The same place can have multiple objects depending on what tab’s selected.
Mikutap
: Website with gorgeous transitions, I wish to replicateTo make an example possibly closer to us, think you’re in a car in the urban traffic. Due to one-way streets, metric is not the best way to organize your perception of the space: actually, the proper topology to do that is possibly not Hausdorff (usually, you can’t move to A without immediately finding yourself in B, and once you are in B, you are enormously far from A, even if you changed your mind about the opportunity of the movement.)
a ~ a -> a
<- automatically make it a domain?
Language with only domains?Think about lex-ordering as some kind of metric. Eg. a, b, c
each define
a branch in space. abc
counts for [a]/4 + [b]/4 + [c]/4
,
where [a] = 1, [b] = 2, [c] =3
. This way, the lowest lex word is the
path that keeps us closest to 0
. See how much of the string stuff
can be reinterpreted this way.
gensim-data
changing the order of downloading
and then trying to pull data locally.SourcePanel : public Panel
versus
Panel a = ...; type SourcePanel = Panel Source
.sizecoding.org
how to build demos, wealth of demoscene knowledge! shows basic MSdos getting startedpouet.net
demoscene grouptinycode
list a = cons a (list a) | nil
. this in sparse form
is linked list, in dense form is array. tree a = nil | branch a (tree a) (tree a)
in
sparse form is tree, in dense form is some dense repr. complete a = leaf a | branch (complete a) (complete a)
is tree in sparse form, heap in dense form.function mk() { let inner = function() { console.warn(this.x)}; inner = inner.bind({x: 42}); inner.x = -42; return inner; }; mk()(); console.log(mk().x);
. NOTE: this behaviour changes if inner
is an arrow function. What are the denotational semantics of this?