System of equations and perturbation methods












0














I would like to characterise how the solution of a nonlinear system of equations change if a perturbation term is added.



Namely, I have the system
begin{array}{lcl} 2y [F(x) - varepsilon frac{1}{y(xy-1)} ] & = & 0 \ y^2 [F^prime (x) -varepsilon frac{y}{xy-1}] & = & 0end{array}



In the unperturbed case $varepsilon = 0$ the solution is handy $$ (x_0,0)$$ where $x_0$ is such that $F^prime (x_0) = 0$.



How to describe the solution for small $varepsilon$??



I would have tried to expand the perturbed terms around the solution of the unperturbed system, but the term $frac{1}{y(xy-1)}$ is not even defined there.



Alternatively, following the perturbation theory one could assume that the perturbed solution can be expressed as
begin{array}{lcl} x & = & x_0 + varepsilon f_1 +varepsilon^2 f_2 + dots \ y = & = & varepsilon g_1 +varepsilon^2 g_2 + dots end{array}



and let me substitute in the first equation of the system.
I get
$$ 2(varepsilon g_11 + varepsilon^2 g_2 + dots ) Big[F(x_0+varepsilon f_1 + dots) - varepsilon frac{1}{(varepsilon g_11 + varepsilon^2 g_2 + dots)((x_0+varepsilon f_1 + dots)(varepsilon g_1 + varepsilon^2 g_2 + dots))}Big]$$ which could develop into



$$2(varepsilon g_1 + varepsilon^2 g_2 + dots )Big[[F(x_0) + F ^{prime prime}(x_0)frac{1}{2}varepsilon^2 f_1^2] - varepsilon frac{1}{x_0varepsilon^2g_1^2 + x_0varepsilon^3g_1g_2 + varepsilon^3 f_1g_1^2 + varepsilon^3x_0 g_1g_2 + dots}Big] $$



Now I need to collect terms that are first order in $epsilon$.



But how to do that systematically?
I am struggling to handle the fraction $$- varepsilon frac{1}{x_0varepsilon^2g_1^2 + x_0varepsilon^3g_1g_2 + varepsilon^3 f_1g_1^2 + varepsilon^3x_0 g_1g_2 + dots}$$



I would be most grateful for any hint.



Thanks and Happiest New 2019



EDIT:
I would like to describe one more attempt of mine.
I thought of replacing the original perturbed system
begin{array}{lcl} 2y [F(x) - varepsilon frac{1}{y(xy-1)} ] & = & 0 \ y^2 [F^prime (x) -varepsilon frac{y}{xy-1}] & = & 0end{array}
with the system



begin{array}{lcl} 2y [F(x) - varepsilon (-frac{1}{y}-x) ] & = & 0 \ y^2 [F^prime (x) -varepsilon (-y)] & = & 0end{array}
using the approximations



$$frac{1}{y(xy-1)} approx -frac{1}{y} -x$$ and $$ frac{y}{xy-1} approx -y$$ first-order valid around $y=0$.
Then I get something tractable, would this be a workaround?



EDIT
Following the comment by User121049, I would like to add, should it be of any interest, that the problem I have is equivalent to finding the stationary point of the function



$$ Z(x,y) = y^2 Big[ F(x) - epsilon [log(frac{1}{y}-x) +1)] Big]$$



the system I originally described is obtained by setting the partial derivatives to zero.






systems-of-equations perturbation-theory







share|cite|improve this question

















This question has an open bounty worth +200
reputation from An aedonist ending in 6 days.


This question has not received enough attention.
















  • "How to understand what happens to the solution for small ϵ" -- what do you mean by "what happens"? Also, both perturbed and unperturbed case, any $(x, 0)$ seems to be a solution
    – Peter Franek
    2 days ago












  • I would like to know how the solution changes when $epsilon$ is small, compared to case when $epsilon$ is $0$. I do not understand how $(x,0)$ can be a solution in the perturbed case, as the term $frac{1}{y(xy-1)} $ is not even defined for $y=0$.
    – An aedonist
    2 days ago












  • At the end of the day, I would like to have a closed form solution of the nonlinear system. That looking unfeasible, I would be content in having a solution for "small" $epsilon$.
    – An aedonist
    2 days ago












  • Are you looking for the extrema of $y^2F(x)$ or is the form a coincidence?
    – user121049
    14 hours ago










  • It is not a coincidence,the unperturbed problem comes exactly for the minimisation problem you mentioned
    – An aedonist
    14 hours ago
















0














I would like to characterise how the solution of a nonlinear system of equations change if a perturbation term is added.



Namely, I have the system
begin{array}{lcl} 2y [F(x) - varepsilon frac{1}{y(xy-1)} ] & = & 0 \ y^2 [F^prime (x) -varepsilon frac{y}{xy-1}] & = & 0end{array}



In the unperturbed case $varepsilon = 0$ the solution is handy $$ (x_0,0)$$ where $x_0$ is such that $F^prime (x_0) = 0$.



How to describe the solution for small $varepsilon$??



I would have tried to expand the perturbed terms around the solution of the unperturbed system, but the term $frac{1}{y(xy-1)}$ is not even defined there.



Alternatively, following the perturbation theory one could assume that the perturbed solution can be expressed as
begin{array}{lcl} x & = & x_0 + varepsilon f_1 +varepsilon^2 f_2 + dots \ y = & = & varepsilon g_1 +varepsilon^2 g_2 + dots end{array}



and let me substitute in the first equation of the system.
I get
$$ 2(varepsilon g_11 + varepsilon^2 g_2 + dots ) Big[F(x_0+varepsilon f_1 + dots) - varepsilon frac{1}{(varepsilon g_11 + varepsilon^2 g_2 + dots)((x_0+varepsilon f_1 + dots)(varepsilon g_1 + varepsilon^2 g_2 + dots))}Big]$$ which could develop into



$$2(varepsilon g_1 + varepsilon^2 g_2 + dots )Big[[F(x_0) + F ^{prime prime}(x_0)frac{1}{2}varepsilon^2 f_1^2] - varepsilon frac{1}{x_0varepsilon^2g_1^2 + x_0varepsilon^3g_1g_2 + varepsilon^3 f_1g_1^2 + varepsilon^3x_0 g_1g_2 + dots}Big] $$



Now I need to collect terms that are first order in $epsilon$.



But how to do that systematically?
I am struggling to handle the fraction $$- varepsilon frac{1}{x_0varepsilon^2g_1^2 + x_0varepsilon^3g_1g_2 + varepsilon^3 f_1g_1^2 + varepsilon^3x_0 g_1g_2 + dots}$$



I would be most grateful for any hint.



Thanks and Happiest New 2019



EDIT:
I would like to describe one more attempt of mine.
I thought of replacing the original perturbed system
begin{array}{lcl} 2y [F(x) - varepsilon frac{1}{y(xy-1)} ] & = & 0 \ y^2 [F^prime (x) -varepsilon frac{y}{xy-1}] & = & 0end{array}
with the system



begin{array}{lcl} 2y [F(x) - varepsilon (-frac{1}{y}-x) ] & = & 0 \ y^2 [F^prime (x) -varepsilon (-y)] & = & 0end{array}
using the approximations



$$frac{1}{y(xy-1)} approx -frac{1}{y} -x$$ and $$ frac{y}{xy-1} approx -y$$ first-order valid around $y=0$.
Then I get something tractable, would this be a workaround?



EDIT
Following the comment by User121049, I would like to add, should it be of any interest, that the problem I have is equivalent to finding the stationary point of the function



$$ Z(x,y) = y^2 Big[ F(x) - epsilon [log(frac{1}{y}-x) +1)] Big]$$



the system I originally described is obtained by setting the partial derivatives to zero.






systems-of-equations perturbation-theory







share|cite|improve this question

















This question has an open bounty worth +200
reputation from An aedonist ending in 6 days.


This question has not received enough attention.
















  • "How to understand what happens to the solution for small ϵ" -- what do you mean by "what happens"? Also, both perturbed and unperturbed case, any $(x, 0)$ seems to be a solution
    – Peter Franek
    2 days ago












  • I would like to know how the solution changes when $epsilon$ is small, compared to case when $epsilon$ is $0$. I do not understand how $(x,0)$ can be a solution in the perturbed case, as the term $frac{1}{y(xy-1)} $ is not even defined for $y=0$.
    – An aedonist
    2 days ago












  • At the end of the day, I would like to have a closed form solution of the nonlinear system. That looking unfeasible, I would be content in having a solution for "small" $epsilon$.
    – An aedonist
    2 days ago












  • Are you looking for the extrema of $y^2F(x)$ or is the form a coincidence?
    – user121049
    14 hours ago










  • It is not a coincidence,the unperturbed problem comes exactly for the minimisation problem you mentioned
    – An aedonist
    14 hours ago














0












0








0







I would like to characterise how the solution of a nonlinear system of equations change if a perturbation term is added.



Namely, I have the system
begin{array}{lcl} 2y [F(x) - varepsilon frac{1}{y(xy-1)} ] & = & 0 \ y^2 [F^prime (x) -varepsilon frac{y}{xy-1}] & = & 0end{array}



In the unperturbed case $varepsilon = 0$ the solution is handy $$ (x_0,0)$$ where $x_0$ is such that $F^prime (x_0) = 0$.



How to describe the solution for small $varepsilon$??



I would have tried to expand the perturbed terms around the solution of the unperturbed system, but the term $frac{1}{y(xy-1)}$ is not even defined there.



Alternatively, following the perturbation theory one could assume that the perturbed solution can be expressed as
begin{array}{lcl} x & = & x_0 + varepsilon f_1 +varepsilon^2 f_2 + dots \ y = & = & varepsilon g_1 +varepsilon^2 g_2 + dots end{array}



and let me substitute in the first equation of the system.
I get
$$ 2(varepsilon g_11 + varepsilon^2 g_2 + dots ) Big[F(x_0+varepsilon f_1 + dots) - varepsilon frac{1}{(varepsilon g_11 + varepsilon^2 g_2 + dots)((x_0+varepsilon f_1 + dots)(varepsilon g_1 + varepsilon^2 g_2 + dots))}Big]$$ which could develop into



$$2(varepsilon g_1 + varepsilon^2 g_2 + dots )Big[[F(x_0) + F ^{prime prime}(x_0)frac{1}{2}varepsilon^2 f_1^2] - varepsilon frac{1}{x_0varepsilon^2g_1^2 + x_0varepsilon^3g_1g_2 + varepsilon^3 f_1g_1^2 + varepsilon^3x_0 g_1g_2 + dots}Big] $$



Now I need to collect terms that are first order in $epsilon$.



But how to do that systematically?
I am struggling to handle the fraction $$- varepsilon frac{1}{x_0varepsilon^2g_1^2 + x_0varepsilon^3g_1g_2 + varepsilon^3 f_1g_1^2 + varepsilon^3x_0 g_1g_2 + dots}$$



I would be most grateful for any hint.



Thanks and Happiest New 2019



EDIT:
I would like to describe one more attempt of mine.
I thought of replacing the original perturbed system
begin{array}{lcl} 2y [F(x) - varepsilon frac{1}{y(xy-1)} ] & = & 0 \ y^2 [F^prime (x) -varepsilon frac{y}{xy-1}] & = & 0end{array}
with the system



begin{array}{lcl} 2y [F(x) - varepsilon (-frac{1}{y}-x) ] & = & 0 \ y^2 [F^prime (x) -varepsilon (-y)] & = & 0end{array}
using the approximations



$$frac{1}{y(xy-1)} approx -frac{1}{y} -x$$ and $$ frac{y}{xy-1} approx -y$$ first-order valid around $y=0$.
Then I get something tractable, would this be a workaround?



EDIT
Following the comment by User121049, I would like to add, should it be of any interest, that the problem I have is equivalent to finding the stationary point of the function



$$ Z(x,y) = y^2 Big[ F(x) - epsilon [log(frac{1}{y}-x) +1)] Big]$$



the system I originally described is obtained by setting the partial derivatives to zero.






systems-of-equations perturbation-theory







share|cite|improve this question















I would like to characterise how the solution of a nonlinear system of equations change if a perturbation term is added.



Namely, I have the system
begin{array}{lcl} 2y [F(x) - varepsilon frac{1}{y(xy-1)} ] & = & 0 \ y^2 [F^prime (x) -varepsilon frac{y}{xy-1}] & = & 0end{array}



In the unperturbed case $varepsilon = 0$ the solution is handy $$ (x_0,0)$$ where $x_0$ is such that $F^prime (x_0) = 0$.



How to describe the solution for small $varepsilon$??



I would have tried to expand the perturbed terms around the solution of the unperturbed system, but the term $frac{1}{y(xy-1)}$ is not even defined there.



Alternatively, following the perturbation theory one could assume that the perturbed solution can be expressed as
begin{array}{lcl} x & = & x_0 + varepsilon f_1 +varepsilon^2 f_2 + dots \ y = & = & varepsilon g_1 +varepsilon^2 g_2 + dots end{array}



and let me substitute in the first equation of the system.
I get
$$ 2(varepsilon g_11 + varepsilon^2 g_2 + dots ) Big[F(x_0+varepsilon f_1 + dots) - varepsilon frac{1}{(varepsilon g_11 + varepsilon^2 g_2 + dots)((x_0+varepsilon f_1 + dots)(varepsilon g_1 + varepsilon^2 g_2 + dots))}Big]$$ which could develop into



$$2(varepsilon g_1 + varepsilon^2 g_2 + dots )Big[[F(x_0) + F ^{prime prime}(x_0)frac{1}{2}varepsilon^2 f_1^2] - varepsilon frac{1}{x_0varepsilon^2g_1^2 + x_0varepsilon^3g_1g_2 + varepsilon^3 f_1g_1^2 + varepsilon^3x_0 g_1g_2 + dots}Big] $$



Now I need to collect terms that are first order in $epsilon$.



But how to do that systematically?
I am struggling to handle the fraction $$- varepsilon frac{1}{x_0varepsilon^2g_1^2 + x_0varepsilon^3g_1g_2 + varepsilon^3 f_1g_1^2 + varepsilon^3x_0 g_1g_2 + dots}$$



I would be most grateful for any hint.



Thanks and Happiest New 2019



EDIT:
I would like to describe one more attempt of mine.
I thought of replacing the original perturbed system
begin{array}{lcl} 2y [F(x) - varepsilon frac{1}{y(xy-1)} ] & = & 0 \ y^2 [F^prime (x) -varepsilon frac{y}{xy-1}] & = & 0end{array}
with the system



begin{array}{lcl} 2y [F(x) - varepsilon (-frac{1}{y}-x) ] & = & 0 \ y^2 [F^prime (x) -varepsilon (-y)] & = & 0end{array}
using the approximations



$$frac{1}{y(xy-1)} approx -frac{1}{y} -x$$ and $$ frac{y}{xy-1} approx -y$$ first-order valid around $y=0$.
Then I get something tractable, would this be a workaround?



EDIT
Following the comment by User121049, I would like to add, should it be of any interest, that the problem I have is equivalent to finding the stationary point of the function



$$ Z(x,y) = y^2 Big[ F(x) - epsilon [log(frac{1}{y}-x) +1)] Big]$$



the system I originally described is obtained by setting the partial derivatives to zero.






systems-of-equations perturbation-theory




systems-of-equations perturbation-theory






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited 14 hours ago

























asked 2 days ago









An aedonist

2,154618




2,154618






This question has an open bounty worth +200
reputation from An aedonist ending in 6 days.


This question has not received enough attention.








This question has an open bounty worth +200
reputation from An aedonist ending in 6 days.


This question has not received enough attention.














  • "How to understand what happens to the solution for small ϵ" -- what do you mean by "what happens"? Also, both perturbed and unperturbed case, any $(x, 0)$ seems to be a solution
    – Peter Franek
    2 days ago












  • I would like to know how the solution changes when $epsilon$ is small, compared to case when $epsilon$ is $0$. I do not understand how $(x,0)$ can be a solution in the perturbed case, as the term $frac{1}{y(xy-1)} $ is not even defined for $y=0$.
    – An aedonist
    2 days ago












  • At the end of the day, I would like to have a closed form solution of the nonlinear system. That looking unfeasible, I would be content in having a solution for "small" $epsilon$.
    – An aedonist
    2 days ago












  • Are you looking for the extrema of $y^2F(x)$ or is the form a coincidence?
    – user121049
    14 hours ago










  • It is not a coincidence,the unperturbed problem comes exactly for the minimisation problem you mentioned
    – An aedonist
    14 hours ago


















  • "How to understand what happens to the solution for small ϵ" -- what do you mean by "what happens"? Also, both perturbed and unperturbed case, any $(x, 0)$ seems to be a solution
    – Peter Franek
    2 days ago












  • I would like to know how the solution changes when $epsilon$ is small, compared to case when $epsilon$ is $0$. I do not understand how $(x,0)$ can be a solution in the perturbed case, as the term $frac{1}{y(xy-1)} $ is not even defined for $y=0$.
    – An aedonist
    2 days ago












  • At the end of the day, I would like to have a closed form solution of the nonlinear system. That looking unfeasible, I would be content in having a solution for "small" $epsilon$.
    – An aedonist
    2 days ago












  • Are you looking for the extrema of $y^2F(x)$ or is the form a coincidence?
    – user121049
    14 hours ago










  • It is not a coincidence,the unperturbed problem comes exactly for the minimisation problem you mentioned
    – An aedonist
    14 hours ago
















"How to understand what happens to the solution for small ϵ" -- what do you mean by "what happens"? Also, both perturbed and unperturbed case, any $(x, 0)$ seems to be a solution
– Peter Franek
2 days ago






"How to understand what happens to the solution for small ϵ" -- what do you mean by "what happens"? Also, both perturbed and unperturbed case, any $(x, 0)$ seems to be a solution
– Peter Franek
2 days ago














I would like to know how the solution changes when $epsilon$ is small, compared to case when $epsilon$ is $0$. I do not understand how $(x,0)$ can be a solution in the perturbed case, as the term $frac{1}{y(xy-1)} $ is not even defined for $y=0$.
– An aedonist
2 days ago






I would like to know how the solution changes when $epsilon$ is small, compared to case when $epsilon$ is $0$. I do not understand how $(x,0)$ can be a solution in the perturbed case, as the term $frac{1}{y(xy-1)} $ is not even defined for $y=0$.
– An aedonist
2 days ago














At the end of the day, I would like to have a closed form solution of the nonlinear system. That looking unfeasible, I would be content in having a solution for "small" $epsilon$.
– An aedonist
2 days ago






At the end of the day, I would like to have a closed form solution of the nonlinear system. That looking unfeasible, I would be content in having a solution for "small" $epsilon$.
– An aedonist
2 days ago














Are you looking for the extrema of $y^2F(x)$ or is the form a coincidence?
– user121049
14 hours ago




Are you looking for the extrema of $y^2F(x)$ or is the form a coincidence?
– user121049
14 hours ago












It is not a coincidence,the unperturbed problem comes exactly for the minimisation problem you mentioned
– An aedonist
14 hours ago




It is not a coincidence,the unperturbed problem comes exactly for the minimisation problem you mentioned
– An aedonist
14 hours ago










0






active

oldest

votes











Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3059318%2fsystem-of-equations-and-perturbation-methods%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























0






active

oldest

votes








0






active

oldest

votes









active

oldest

votes






active

oldest

votes
















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid …



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.





Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


Please pay close attention to the following guidance:


  • Please be sure to answer the question. Provide details and share your research!

But avoid …



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3059318%2fsystem-of-equations-and-perturbation-methods%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







-

Popular posts from this blog

1300-talet

Image
Den här artikeln handlar om hundraårsperioden 1300–1399. För decenniet 1300–1309, se 1300-talet (decennium). .mw-parser-output .infobox{border:1px solid #aaa;background-color:#f9f9f9;color:black;margin:.5em 0 .5em 1em;padding:.2em;float:right;clear:right;width:22em;text-align:left;font-size:88%;line-height:1.6em}.mw-parser-output .infobox td,.mw-parser-output .infobox th{vertical-align:top;padding:0 .2em}.mw-parser-output .infobox caption{font-size:larger}.mw-parser-output .infobox.bordered{border-collapse:collapse}.mw-parser-output .infobox.bordered td,.mw-parser-output .infobox.bordered th{border:1px solid #aaa}.mw-parser-output .infobox.bordered .borderless td,.mw-parser-output .infobox.bordered .borderless th{border:0}.mw-parser-output .infobox-showbutton .mw-collapsible-text{color:inherit}.mw-parser-output .infobox.bordered .mergedtoprow td,.mw-parser-output .infobox.bordered .mergedtoprow th{border:0;border-top:1px solid #aaa;border-right:1px solid #aaa}.mw-parser-output ...
Read more

1300-talet

Image
Den här artikeln handlar om hundraårsperioden 1300–1399. För decenniet 1300–1309, se 1300-talet (decennium). .mw-parser-output .infobox{border:1px solid #aaa;background-color:#f9f9f9;color:black;margin:.5em 0 .5em 1em;padding:.2em;float:right;clear:right;width:22em;text-align:left;font-size:88%;line-height:1.6em}.mw-parser-output .infobox td,.mw-parser-output .infobox th{vertical-align:top;padding:0 .2em}.mw-parser-output .infobox caption{font-size:larger}.mw-parser-output .infobox.bordered{border-collapse:collapse}.mw-parser-output .infobox.bordered td,.mw-parser-output .infobox.bordered th{border:1px solid #aaa}.mw-parser-output .infobox.bordered .borderless td,.mw-parser-output .infobox.bordered .borderless th{border:0}.mw-parser-output .infobox-showbutton .mw-collapsible-text{color:inherit}.mw-parser-output .infobox.bordered .mergedtoprow td,.mw-parser-output .infobox.bordered .mergedtoprow th{border:0;border-top:1px solid #aaa;border-right:1px solid #aaa}.mw-parser-output ...
Read more

Display a custom attribute below product name in the front-end Magento 1.9.3.8

Image
0 I need to display a custom attribute bellow the product name and I don't know how can I call this attribute. I am editing the file /app/design/frontend/templatemela/MAG100219_1/template/catalog/product/view.phtml But how can I call this attribute in php? I tried calling a string echo with the name I put in the attribute, but it didn't work. Code is as below: <div class="page-title product-title"> <h1><?php echo $_helper->productAttribute($_product, $_product->getName(), 'name') ?></h1> </div> <div class="codigoinmetro"> <h2><?php echo $_helper->productAttribute($_product, $_product->getName(), 'registroinmetro') ?></h2> </div> php attrib...
Read more