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### [Solved] Modern Algebra Symbols

Posted:

**Fri Jun 08, 2018 2:22 am**
by **MH7**

I have noticed that there are some symbols that are used in Modern (abstract) Algebra, that aren't necessarily listed in the math reference. "oplus", indicating a direct product between 2 groups, is one such example. I would like to track down a few others.

My most pressing need, is the sign for "is isomorphic to". (a tilde above an equal sign) How do I make this?

### Re: Modern Algebra Symbols

Posted:

**Fri Jun 08, 2018 4:48 am**
by **UnklDonald418**

Insert %Ux2245 into the appropriate place in your formula to display the character I believe you are needing.

To find other symbols, in the Math module select Tools>Symbols to open the Symbols dialog.

Select Special for Symbol Set and the click on Edit to open the Edit Symbols dialog.

### Re: Modern Algebra Symbols

Posted:

**Fri Jun 08, 2018 5:10 am**
by **MH7**

OK, that's really clunky, but it works. The only question is, how do I put a slash through it, to indicate "is not isomorphic to"?

Thank you.

### Re: Modern Algebra Symbols

Posted:

**Fri Jun 08, 2018 6:15 am**
by **UnklDonald418**

that's really clunky, but it works.

If you use the

Edit Symbols dialog I mentioned, you can add the symbol to the list of

Special symbols. Once on the list you can select it in the

Symbols dialog and

Insert it into your formula.

how do I put a slash through it, to indicate "is not isomorphic to"?

The Unicode value should be

%Ux2247 but it doesn't seem to work so it may not be available in the Math module.

### Re: Modern Algebra Symbols

Posted:

**Fri Jun 08, 2018 7:16 am**
by **Zizi64**

My most pressing need, is the sign for "is isomorphic to". (a tilde above an equal sign) How do I make this?

I just tried it in my LibreOffice 5.4.7:

for the ≅ sign like character (it will be a composed character but not one standalone Unicode character):

- Code: Select all Expand viewCollapse view
`tilde "=" `

For the "approximately equals" sign:

- Code: Select all Expand viewCollapse view
`simeq`

And I can write Oplus characters in my LO. Maybe the working of this feature is depends on the installed Symbols character set. There are obsolete Symbols set in some version of the operating systems.

### Re: Modern Algebra Symbols

Posted:

**Fri Jun 08, 2018 11:49 am**
by **keme**

The congruence/isomorphism symbol is hex unicode 2245.

- Code: Select all Expand viewCollapse view
`A boper %Ux2245 B`

"Boper" is perhaps not strictly necessary. It makes the symbol behave like a binary operator, which improves layout in some situations (and may also aid in discovering structural inconsistencies in your formula).

### Re: Modern Algebra Symbols

Posted:

**Fri Jun 08, 2018 4:04 pm**
by **MH7**

Thank you everyone for the suggestions. Regarding the "clunky" use of the special characters, I say that it was clunky, because in the formula editor, it would not allow me to directly insert using the Unicode. I did, indeed, have to add it to the special characters menu, under "edit". And it seems that is a limited palette.

Now, the pressing issue, is the question that was missed in here... Where is the "not isomorphic to" symbol? How can I put a slash through what we've just discovered, to negate its value?

### Re: Modern Algebra Symbols

Posted:

**Fri Jun 08, 2018 4:17 pm**
by **MrProgrammer**

MH7 wrote:Where is the "not isomorphic to" symbol?

Perhaps you can use:

tilde "≠"

If this solved your problem please go to your first post use the Edit button and add [Solved] to the start of the title. You can select the green checkmark icon at the same time.

### Re: Modern Algebra Symbols

Posted:

**Fri Jun 08, 2018 4:56 pm**
by **MH7**

It works OK (doesn't quite look right) in the document, but not in the math editor.

### Re: Modern Algebra Symbols

Posted:

**Fri Jun 08, 2018 5:22 pm**
by **UnklDonald418**

how do I put a slash through it, to indicate "is not isomorphic to"?

I found it in the

Arial Unicode MS font. Set the

Edit Symbol dialog like this

Select the symbol and push the Add button. Then it should appear in the

Symbols dialog Special list.

### Re: Modern Algebra Symbols

Posted:

**Sat Jun 09, 2018 6:26 pm**
by **MH7**

THank you, that will do it.