ios – Why is the controller fired when it has a strong reference cycle?

I have a simple example to check if the delegate has a strong reference and my controller is dismissed when I close it.

Here is first class:

Class ViewController: UIViewController {

prepare func (for selection: UIStoryboardSegue, sender: any?) {
if we denote = segue.identifier {
if identifier == "second" {
let dvc = segue.destination as! Second View Controller
dvc.delegate = self

Extension ViewController: SecondViewControllerDelegate {
func someMethod () {
print ("method called")

The second class and the protocol:

Protocol SecondViewControllerDelegate {
func someMethod ()

SecondViewController class: UIViewController {

var delegate: SecondViewControllerDelegate?

override func viewDidLoad () {
super.viewDidLoad ()
delegate? .Method ()

@IBAction func returnBack (UIButton button) {
self.dismiss (animated: true, completion: null)

print ("second controller released")

I did not classify my delegates as weak to verify the theory. When I close my second controller, I have a real message in the console that's in the Deinit method.
Why do not I have a strong reference cycle or if that's why my controller can be fired?

Many Thanks!

Reference requirement – Alberti Rank 1 set and an inflatable argument

In this paper stands the rank of Alberti
says that the unique part $ D ^ s u $ in memory of $ mathcal L ^ d $ of the sales derivative $ You $ a function $ u in BV_ {loc} ( mathbb R ^ d; mathbb R ^ m) $ may be
written, in polar decomposition, as $ D ^ su = xi otimes eta | D ^ su | $,

Then, "by a standard inflation argument, this implies the near to $ | D ^ s u | $-a.e. Point $ x $ asymptotically $ u (y) $ behaves like a function that has a single nonzero component, parallel to $ eta (x) in mathbb {S} ^ {m-1} $and depending on a single scalar variable, the component of $ y $ a long $ xi (x) in mathbb {S} ^ {d-1} $".

  1. What does the statement in quotes heuristically mean?
  2. How can this be proved exactly (ie, could you explain the details of the above "standard blow-up argument")?
  3. Where can I find a picture to illustrate this situation?

A more general question was asked in the sentence of Alberti rank one. A related topic is Alberti's Rank 1 sentence and the reduction of BV's function to the two-dimensional case.

Reference Request – Unbound component of the Fredholm domain

To let $ X $ to be a Banach room and $ T in mathcal L (X) $,

The authors Engel and Nagel present in their book "One-parameter semi-groups for linear evolution equations" on page 27. 248 the concept of Fredholm domain from $ T $ defined by
$$ rho_F (T): = { lambda in mathbb C: lambda – T text {is a Fredholm operator} }. $$
The next page states:

"Here we only remember that the poles of $ R ( cdot, T) $ with finite algebraic multiplicity belong to it $ rho_F (T) $, Conversely, an element of the unbound connected component of $ rho_F (T) $ either belongs to $ rho (T) $ or is a pole of finite algebraic plurality. "

I can prove the first statement in a very elementary way by using properties of spectral projections and some very basic function calculations. The second statement, however, seems difficult to prove. In the quoted literature, I found proof of the Stament (compare the proof Corollary XI.8.5 in "Classes of Linear Operators Vol. I" by Gohberg, Goldberg and Kaashoek). But it seems to rely on some theorems about Fredholm operator functions.

So my question is whether there is a more elementary way to see that the statement is true, perhaps only by using some basic facts about spectral projections. I thought for a long time that I could not prove it. Is there perhaps a reference for the statement that uses more elementary arguments? Or does anyone else know how to prove it? I look forward to your answers.

Hooks – Change the term reference in Drupal 7

I added a term reference field to a content type. I would like to change the term reference list. I searched the site, but no information is found. Can someone help me how to change the term reference list.

Current terms are displayed as follows: term1, term2

but I want to add more field data, eg ex: term1 (count-2), term2 (count-3)

Term reference:

Enter the image description here

Reference requirement – difference for quotient solutions of the ODE and Liouville equations

Suppose that $ Phi $ is the solution of
$$ begin {cases}
frac {d} {dt} Phi (x, t) = f ( Phi (x, t), t) quad t> 0
Phi (x, 0) = x quad x in mathbb {R} ^ N
end {cases} $$

How do you prove that?
$$ tilde Phi (x, y, t) = left ( Phi (x, t), frac { Phi (x + ry, t) – Phi (x, t)} {r} right) $$
is the river of the ODE with
$$ tilde {f} _r (x, y, t) = left (f (x, t), frac {f (x + ry, t) – f (x, t)} {r} right ) $$
as a vector field?

In an answer to evidence that the flux of a divergence-free vector field is knife-preserving, it has also been proved that $ mu_t = ( Phi ( cdot, t)) _ { sharp} mu $ designate the image of the measure $ mu $ by the river of $ f $then the family of measures $ { mu_t } _ {t in mathbb R} $ meets the Liouville equation
begin {cases}
partial_t mu_t + operatorname {div ,} (f mu_t) = 0 \
mu_0 = mu
end {cases}

in the sense of distributions.

What does PDE do? $ tilde mu_t = ( tilde Phi_t) _ { sharp} mu $ to solve?

8 – Show multiple entity reference field as draggable in node edit form?

You can get multiple values ​​in a table format with the draggable option if you want autocomplete Widget for this field below Manage form display for this content type (Not the Auto completion (tags style)).

If your field accepts an unlimited number of values, the widget is displayed as an autocomplete input field with a button Add another article, As you add more items, you can rearrange the order of the values ​​by dragging and dropping.

Entity Reference Autocomplete widget Unlimited values

You can also get this widget using the Inline Entities Form widget (with the Inline Entity Form plug-in).

soft question – reference request for Grothendiek's thesis "Integration with Values ​​in a Topological Group"

Disclaimer. This question has already been asked in Mathematics Stack Exchange (see link here). I wanted the question to be migrated here, but I was told by a moderator that an old question should not be migrated (something I did not know before).

I recently read the available part of the second part of W. Scharlau's book on Alexandre Grothendieck (see here). There I found

An anecdote survives as Grothendieck arrived at Nancy: the story of his rude reception by Dieudonné, when he showed him a dense handwritten manuscript on "generalized integrals" on his first contact. He had already mentioned this work in writing to Dieudonné and received a warm and friendly reply in which Dieudonné praised his "passion for mathematics". However, Dieudonné's initial receptivity did not survive the first look at the actual text. Those who remember this incident (or rather Dieudonné's account of it) claim that Dieudonné Grothendieck has a
quite disguised, the work showed a despicable tendency to an unfounded generality.

Later it is also mentioned that (as Schwartz tells in his autobiography),

He first gave Dieudonné an article of about fifty pages about "Integration with Values ​​in a Topological Group". It was right, but absolutely uninteresting. Dieudonné, with the (always temporary) aggressiveness he was capable of, gave him a catchy rant and demanded that one should not work that way just to generalize the pleasure. The problem considered had to be difficult and applicable to the rest of the mathematics
(or other sciences); His results would never be useful to anyone.


  1. Does anyone know how Grothendieck dealt with the problem of integration with values ​​in a topological group that he presented to Dieudonné (I seem to find nothing on the internet)?

  2. Why was Grothendiek's work on "Integration with Values ​​in a Topological Group" by Dieudonné described as "not useful to anyone"?

  3. Was this topic researched in the future?

  4. Where can I find (if at all possible) the original work by Grothendieck on the Internet? – High cpm up to $ 10, reference -25%, monthly payments


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