Matrices as Outer Direct Sum of Vector Spaces











up vote
0
down vote

favorite












So studying linear algebra I encountered the outer direct sum and the direct product of collections of vector spaces (which are the same if the collections are finite). When thinking about the uses of these operations (within the reals of linear algebra, that is), I thought about matrices; so now the question:



Can/Should one think of elements of the outer direct sum as matrices?



And if so, could one then generalize, through this thinking, the notion of matrices to infinite matrices?



Thanks in advance!










share|cite|improve this question






















  • If $V$ and $W$ are separate vector spaces, you should think of elements of the outer direct sum $V oplus W$ as being pairs $(v, w)$ with the scalar action $lambda (v, w) = (lambda v, lambda w)$. It can also be useful to consider $(v, w)$ as a column vector, since this is compatible with block matrices. But I wouldn’t think of an element of $V oplus W$ as a matrix.
    – Joppy
    Nov 17 at 7:41















up vote
0
down vote

favorite












So studying linear algebra I encountered the outer direct sum and the direct product of collections of vector spaces (which are the same if the collections are finite). When thinking about the uses of these operations (within the reals of linear algebra, that is), I thought about matrices; so now the question:



Can/Should one think of elements of the outer direct sum as matrices?



And if so, could one then generalize, through this thinking, the notion of matrices to infinite matrices?



Thanks in advance!










share|cite|improve this question






















  • If $V$ and $W$ are separate vector spaces, you should think of elements of the outer direct sum $V oplus W$ as being pairs $(v, w)$ with the scalar action $lambda (v, w) = (lambda v, lambda w)$. It can also be useful to consider $(v, w)$ as a column vector, since this is compatible with block matrices. But I wouldn’t think of an element of $V oplus W$ as a matrix.
    – Joppy
    Nov 17 at 7:41













up vote
0
down vote

favorite









up vote
0
down vote

favorite











So studying linear algebra I encountered the outer direct sum and the direct product of collections of vector spaces (which are the same if the collections are finite). When thinking about the uses of these operations (within the reals of linear algebra, that is), I thought about matrices; so now the question:



Can/Should one think of elements of the outer direct sum as matrices?



And if so, could one then generalize, through this thinking, the notion of matrices to infinite matrices?



Thanks in advance!










share|cite|improve this question













So studying linear algebra I encountered the outer direct sum and the direct product of collections of vector spaces (which are the same if the collections are finite). When thinking about the uses of these operations (within the reals of linear algebra, that is), I thought about matrices; so now the question:



Can/Should one think of elements of the outer direct sum as matrices?



And if so, could one then generalize, through this thinking, the notion of matrices to infinite matrices?



Thanks in advance!







linear-algebra direct-sum direct-product






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Nov 17 at 2:27









BlondCafé

71




71












  • If $V$ and $W$ are separate vector spaces, you should think of elements of the outer direct sum $V oplus W$ as being pairs $(v, w)$ with the scalar action $lambda (v, w) = (lambda v, lambda w)$. It can also be useful to consider $(v, w)$ as a column vector, since this is compatible with block matrices. But I wouldn’t think of an element of $V oplus W$ as a matrix.
    – Joppy
    Nov 17 at 7:41


















  • If $V$ and $W$ are separate vector spaces, you should think of elements of the outer direct sum $V oplus W$ as being pairs $(v, w)$ with the scalar action $lambda (v, w) = (lambda v, lambda w)$. It can also be useful to consider $(v, w)$ as a column vector, since this is compatible with block matrices. But I wouldn’t think of an element of $V oplus W$ as a matrix.
    – Joppy
    Nov 17 at 7:41
















If $V$ and $W$ are separate vector spaces, you should think of elements of the outer direct sum $V oplus W$ as being pairs $(v, w)$ with the scalar action $lambda (v, w) = (lambda v, lambda w)$. It can also be useful to consider $(v, w)$ as a column vector, since this is compatible with block matrices. But I wouldn’t think of an element of $V oplus W$ as a matrix.
– Joppy
Nov 17 at 7:41




If $V$ and $W$ are separate vector spaces, you should think of elements of the outer direct sum $V oplus W$ as being pairs $(v, w)$ with the scalar action $lambda (v, w) = (lambda v, lambda w)$. It can also be useful to consider $(v, w)$ as a column vector, since this is compatible with block matrices. But I wouldn’t think of an element of $V oplus W$ as a matrix.
– Joppy
Nov 17 at 7:41















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',
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%2f3001900%2fmatrices-as-outer-direct-sum-of-vector-spaces%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown






























active

oldest

votes













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%2f3001900%2fmatrices-as-outer-direct-sum-of-vector-spaces%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

Biblatex bibliography style without URLs when DOI exists (in Overleaf with Zotero bibliography)

ComboBox Display Member on multiple fields

Is it possible to collect Nectar points via Trainline?