Simple Issue of oh symbol - exact sequences

In summary, the conversation discusses a possible typo in Adhikari and Adhikari's book "Basic Modern Algebra with Applications" in Section 9.7 Exact Sequences. The authors use an oh symbol (O) instead of a zero symbol (0) in the exact sequences. However, it is believed that this is a mistake and the correct symbol should be a zero. This belief is confirmed by another person in the conversation who explains that the authors are using $O$ to denote the $R$-module that consists of a single element $0$. Additionally, it is noted that in the first line of the proof of Theorem 9.7.1, the symbol should be changed to $0_M
  • #1
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I am reading Adhikari and Adhikari's (A&A) book, "Basic Modern Algebra with Applications".

I am currently focussed on Section 9.7 Exact Sequences. On page 387, A&A give Theorem 9.7.1.

A&A use symbol in the exact sequences that looks like an oh but I think it should be a zero. They continue this 'mistake' or printing error until the end of the page with Example 9.7(d) where the book reverts to a zero symbol in the exact sequence.

I believe the oh symbol is a typo - I think it should be a zero - can someone please confirm that I am correct ...

Page 387 of A&A follows:View attachment 3627

I would very much appreciate someone confirming that the oh symbol (O) in the above text should be a zero (0) ...

Peter
 
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  • #2
I think that the authors are using $O$ to denote the $R$-module that consists of a single element $0$ (or you could call the element $0_O$, to denote that it is the zero element of the module $O$). But in the first line of the proof of Theorem 9.7.1, "$\ker f = \{O_M\}$" should surely be "$\ker f = \{0_M\}$": the kernel of $f$ is the submodule of $M$ consisting of the zero element of $M$.
 
  • #3
Opalg said:
I think that the authors are using $O$ to denote the $R$-module that consists of a single element $0$ (or you could call the element $0_O$, to denote that it is the zero element of the module $O$). But in the first line of the proof of Theorem 9.7.1, "$\ker f = \{O_M\}$" should surely be "$\ker f = \{0_M\}$": the kernel of $f$ is the submodule of $M$ consisting of the zero element of $M$.
Thanks so much Opalg ... appreciate the clarification ... most helpful ...

Peter
 

FAQ: Simple Issue of oh symbol - exact sequences

What is the "oh" symbol used for in exact sequences?

The "oh" symbol, denoted as "0", represents the zero object in a category. In exact sequences, it is used to denote the trivial object, which has no non-zero morphisms to or from any other object in the sequence.

How is the "oh" symbol used in exact sequences?

In exact sequences, the "oh" symbol is typically placed between two objects in the sequence to indicate that there are no non-zero morphisms between them. This helps to define the exactness of the sequence and its properties.

Can the "oh" symbol be used in other mathematical contexts?

Yes, the "oh" symbol has various uses in mathematics, such as representing the cardinality of a set or the order of an element in a group. It can also be used in algebraic equations as a placeholder for a missing value.

Is the "oh" symbol the same as the number zero?

No, while the "oh" symbol is often used to represent zero, it is not the same as the number zero. The "oh" symbol is a mathematical symbol used in specific contexts, whereas zero is a number with various mathematical properties.

Why is the "oh" symbol sometimes referred to as the "zero object"?

The "oh" symbol is referred to as the "zero object" because it represents the object in a category that has no non-zero morphisms to or from any other object. It is also sometimes called the "initial object" or "null object".

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