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Personal comment: I feel that the two currently existing answers may be together creating some confusion on the subject of the question. I hope to address that with my answer, which would actually be more suited as a comment, were it not so long. I hope that it will not result in even more confusion. Finally, please do let me know in case I am the one who is confused. $\newcommand{\Ab}{\mathrm{Ab}} \newcommand{\To}{\longrightarrow} \newcommand{\rightset}[2]{#2\rlap{\scriptstyle #1}}$

Peter May's answer is quite interesting and — very importantly — cautions us to pay attention to the necessary details. On the other hand, I believe his answer brings some unnecessary sophistication to a rather simple situation. More precisely, I think that Dylan Wilson's original answer, while it ignored all details, was essentially correct. The only subtle point is the functorial identification of the $E^2$-term of a Serre fibration $f:E\to B$, which fundamentally requires doing without a basepoint for $B$, and without the corresponding distinguished fibre of $f$.

As Peter May asserts, in the description of the Serre spectral sequence for a fibration $f:E\to B$, one usually assumes:

1. $B$ is path connected, and pointed;

2. the action of $\pi_1 B$ on $H_\ast F$ is trivial, where $F$ is the fibre of $f$ over the basepoint of $B$.

The second hypothesis is a useful simplification which applies in most cases. Moreover, together with condition 1, it allows us to write the $E^2$-term in the following neat, well-known form: $$ E^2_{p,q}=H_p(B,H_q(F)) \qquad\qquad \text{(I)} $$ Obviously, without choosing a basepoint for $B$ that expression does not even make sense! Regardless, we can construct the Serre spectral sequence more generally: see, for example, the book More concise algebraic topology by Peter May and Kate Ponto for a generalization in which condition 2 does not necessarily hold.

For reference, I will briefly describe a common construction of the Serre spectral sequence for any Serre fibration $f:E\to B$; no assumptions are made on $B$ or $f$. We will construct it, without loss of generality, when $B$ is a CW-complex. Then, for a general topological space $B$, we first replace it with a functorial CW-approximation, and pull back the fibration along that approximation. Importantly, the CW-approximation gives a functor from the category of topological spaces to the category of CW-complexes and cellular maps.

Note that the functoriality of the above spectral sequence (even starting from the $E^1$-term) with respect to maps of Serre fibrations is assured by:

• the functoriality of the CW-approximation of a space;

• the functoriality of the spectral sequence associated with a filtered chain complex.

A map of Serre fibrations $f\to \overline{f}$ is simply a commutative square $$ \begin{matrix} E & \To & \overline{E} \\ \rightset{f}{\Big\downarrow} & & \rightset{\overline{f}}{\Big\downarrow} \\ B & \To & \overline{B} \\ \end{matrix} $$ In particular, if $G$ acts on a Serre fibration by such maps, then we automatically obtain an induced action of $G$ on the corresponding Serre spectral sequence. It follows readily that the spectral sequence becomes a spectral sequence of $G$-modules, which converges to the homology of the total space seen as a $G$-module. This is a simple consequence of the exactness of the forgetful functor from $G$-modules to abelian groups. This should answer the question, apart from the identification of the $E^2$-term, which is discussed below.

Indispensably, the fibre of the Serre fibration did not actually figure into the above construction of the Serre spectral sequence. In fact, the fibres only make an appearance once one tries to compute the $E^2$-term. Nevertheless, one can also identify the $E^2$-term in this general case, and moreover, in a functorial manner. The $E^2$-term of the general Serre spectral sequence described above is naturally isomorphic to (which I write here as equal) $$ E^2_{p,q}=H_p(B,H_q(F_\bullet)) \qquad\qquad \text{(II)} $$ with the naturality holding with respect to Serre fibrations $f:E\to B$, and maps of Serre fibrations. Here is a description of the right hand side of (II). Let $F_x=f^{-1}(x)$ be the fibre of $f$ over $x\in B$. In the above expression, $H_q(F_\bullet)$ represents the system of local coefficients on $B$ corresponding to the functor $$ H_q(F_\bullet):\Pi_1(B)\To\Ab $$ from the fundamental groupoid of $B$ to the category of abelian groups. This functor takes a point $x\in B$ to $H_q(F_x)$, and a path homotopy class $[\gamma]$ of paths in $B$ to the map induced by the monodromy along $\gamma$ on the homology of the fibres over the endpoints of $\gamma$. Then the right hand side of (II) is the homology of $B$ for this system of local coefficients. It is straightforward to check this homology is indeed functorial with respect to maps of Serre fibrations.

Disclaimer: I believe (note the emphasis) that the above functorial identification of the $E^2$-term follows the same recipe as the usual derivation of the isomorphism (I) when $B$ is pointed and the fibration is orientable (conditions 1 and 2 above). To be honest, I have not carefully checked the details myself! Please let me know if I am in error. It appears to be considered folklore knowledge. Nevertheless, I cannot actually provide a complete reference to the identification (II) of the $E^2$-term. The only textbooks I have found which refer to local coefficients in the Serre spectral sequence are the aforementioned book by May and Ponto, and McCleary's A user guide to spectral sequences. The former skips the proof in the general case, but at first sight the proof in McCleary's book does seem to give (II) as a natural isomorphism, even if the result is not stated explicitly. Can anyone provide a better reference?

In particular, this functorial identification of the $E^2$-term finishes the answer to the question: the $E^2$-term, identified as the right hand side of (II), becomes a $G$-module in the canonical manner when $G$ acts on a Serre fibration. The fundamental ingredient was that (II) removed any reference to a basepoint of the base space $B$.

Personal comment: I feel that the two previous answers may be together creating some confusion on the subject of the question. I wish to address that with my answer, which would be more suited as a comment, were it not so long. I certainly hope my contribution will not result in even more confusion. $\newcommand{\Ab}{\mathrm{Ab}} \newcommand{\To}{\longrightarrow} \newcommand{\rightset}[2]{#2\rlap{\scriptstyle #1}} \newcommand{\leftset}[2]{\llap{\scriptstyle #1}#2} \newcommand{\label}[1]{\qquad\qquad \text{#1}}$

Peter May's answer is quite interesting and, incisively, cautions us to pay attention to the requisite details. On the other hand, I believe his answer brings some unnecessary sophistication to a rather simple situation. More precisely, I think that Dylan Wilson's original answer, while it ignored all details, was essentially correct (if one replaces "fibre sequences" by "fibrations" in what he writes). The only subtle point is the functorial identification of the $E^2$-term of a Serre fibration $f:E\to B$, which fundamentally requires doing without a basepoint for $B$, and without the corresponding distinguished fibre of $f$.

As Peter May indicates, in the description of the Serre spectral sequence for a fibration $f:E\to B$, one usually assumes:

1. $B$ is path connected, and pointed;

2. the monodromy action of $\pi_1 B$ on $H_\ast F$ is trivial, where $F$ is the fibre of $f$ over the basepoint of $B$.

The second condition is a useful simplification which applies in most cases. Moreover, together with hypothesis 1, it allows us to write the $E^2$-term in the following neat, well-known form: $$ E^2_{p,q}=H_p(B,H_q(F)) \label{(I)} $$ Obviously, without choosing a basepoint for $B$ that expression does not even make sense! Regardless, we can construct the Serre spectral sequence more generally: see, for example, the book More concise algebraic topology by Peter May and Kate Ponto for a generalization in which condition 2 does not necessarily hold.

For reference, I will briefly describe a common construction of the Serre spectral sequence for any Serre fibration $f:E\to B$; no assumptions are made on $B$ or $f$. We will construct it, without loss of generality, when $B$ is a CW-complex. Then, for a general topological space $B$, we first replace it with a functorial CW-approximation, and pull back the fibration $f:E\to B$ along the natural map from the approximation to $B$. Importantly, the CW-approximation gives a functor from the category of topological spaces to the category of CW-complexes and cellular maps.

Observe that the functoriality of the above spectral sequence (even starting from the $E^1$-term) with respect to maps of Serre fibrations is assured by:

• the naturality of the CW-approximation of a space;

• the functoriality of the spectral sequence associated with a filtered chain complex.

A map of Serre fibrations $f\to \overline{f}$ is simply a commutative square $$ \begin{matrix} E & \To & \overline{E} \\ \leftset{f}{\Big\downarrow} & & \rightset{\overline{f}}{\Big\downarrow} \\ B & \To & \overline{B} \\ \end{matrix} $$ In particular, if a group $G$ acts on a Serre fibration by such maps, then we automatically obtain an induced action of $G$ on the corresponding Serre spectral sequence. Therefore, it becomes a spectral sequence of $G$-modules converging to the homology of the total space seen as a $G$-module. This is an immediate consequence of the exactness of the forgetful functor from $G$-modules to abelian groups. That conclusion should answer the question, apart from the identification of the $E^2$-term, which is discussed below.

Indispensably, the fibre of the Serre fibration did not actually figure into the above construction of the Serre spectral sequence. In fact, the fibres only make an appearance once one tries to compute the $E^2$-term. Nevertheless, one can also identify the $E^2$-term in this general case, and moreover, in a functorial manner. Given a Serre fibration $f:E\to B$, the $E^2$-term of the general Serre spectral sequence described above is naturally isomorphic to (which I write here as equal) $$ E^2_{p,q}=H_p(B,H_q(F_\bullet)) \label{(II)} $$ with the naturality holding with respect to maps of Serre fibrations. Here is a description of the right hand side of (II). Let $F_x=f^{-1}(x)$ be the fibre of $f$ over $x\in B$. In the above expression, $H_q(F_\bullet)$ represents the system of local coefficients on $B$ corresponding to the functor $$ H_q(F_\bullet):\Pi_1(B)\To\Ab $$ from the fundamental groupoid of $B$ to the category of abelian groups. This functor takes a point $x\in B$ to $H_q(F_x)$, and a path homotopy class $[\gamma]$ of paths in $B$ to the map induced by the monodromy along $\gamma$ on the homology of the fibres over the endpoints of $\gamma$. Then the right hand side of (II) is the homology of $B$ for this system of local coefficients. It is straightforward to check this homology is indeed functorial with respect to maps of Serre fibrations.

Disclaimer: I believe that the functorial identification (II) of the $E^2$-term follows the same recipe as the usual derivation of the isomorphism (I) obtained under conditions 1 and 2. To be honest, I have not carefully checked the details myself! Please let me know if I am in error. It appears to be considered folklore knowledge. Nevertheless, I cannot actually provide a complete reference to the identification (II) of the $E^2$-term. The only textbooks I have found which refer to local coefficients in the Serre spectral sequence are the aforementioned book by May and Ponto, and McCleary's A user guide to spectral sequences. The former skips the proof in the general case, but at first sight the proof in McCleary's book does seem to give (II) as a natural isomorphism, even if the result is not stated explicitly. Can anyone provide a better reference?

In particular, this functorial identification of the $E^2$-term finishes the answer to the question. The $E^2$-term, identified as the right hand side of (II), becomes a $G$-module in the canonical manner when $G$ acts on a Serre fibration. The fundamental ingredient was that (II) removed any reference to a basepoint of the base space of the fibration.

Peter May's answer is quite interesting and — very importantly — cautions us to pay attention to the necessary details. On the other hand, I believe his answer adds needless complication to a rather simple situation. More precisely, I think that Dylan Wilson's original answer, while it ignored all details, was essentially correct. The only subtle point is the functorial identification of the $E^2$-term of a Serre fibration $f:E\to B$, which fundamentally requires doing without a basepoint for $B$, and without the corresponding distinguished fibre of $f$.

Peter May asserts correctly that in the description of the Serre spectral sequence for a fibration $f:E\to B$, one usually assumes:

Peter May's answer is quite interesting and — very importantly — cautions us to pay attention to the necessary details. On the other hand, I believe his answer brings some unnecessary sophistication to a rather simple situation. More precisely, I think that Dylan Wilson's original answer, while it ignored all details, was essentially correct. The only subtle point is the functorial identification of the $E^2$-term of a Serre fibration $f:E\to B$, which fundamentally requires doing without a basepoint for $B$, and without the corresponding distinguished fibre of $f$.

As Peter May asserts, in the description of the Serre spectral sequence for a fibration $f:E\to B$, one usually assumes:

Indispensably, the fibre of the Serre fibration did not actually figure into the above construction of the Serre spectral sequence. In fact, the fibres only make an appearance once one tries to compute the E^2-term. Nevertheless, one can also identify the $E^2$-term in this general case, and moreover, in a functorial manner. The $E^2$-term of the general Serre spectral sequence described above is naturally isomorphic to (which I write here as equal) $$ E^2_{p,q}=H_p(B,H_q(F_\bullet)) \qquad\qquad \text{(II)} $$ with the naturality holding with respect to Serre fibrations $f:E\to B$, and maps of Serre fibrations. Here is a description of the right hand side of (II). Let $F_x=f^{-1}(x)$ be the fibre of $f$ over $x\in B$. In the above expression, $H_q(F_\bullet)$ represents the system of local coefficients on $B$ corresponding to the functor $$ H_q(F_\bullet):\Pi_1(B)\To\Ab $$ from the fundamental groupoid of $B$ to the category of abelian groups. This functor takes a point $x\in B$ to $H_q(F_x)$, and a path homotopy class $[\gamma]$ of paths in $B$ to the map induced by the monodromy along $\gamma$ on the homology of the fibres over the endpoints of $\gamma$. Then the right hand side of (II) is the homology of $B$ for this system of local coefficients. It is straightforward to check this homology is indeed functorial with respect to maps of Serre fibrations.

Disclaimer: I believe (note the emphasis) that the above functorial identification of the $E^2$-term follows the same recipe as the usual derivation of the isomorphism (I) when $B$ is pointed and the fibration is orientable (conditions 1 and 2 above). To be honest, I have not carefully checked the details myself! Please let me know if I am in error. It appears to be considered folklore knowledge. Nevertheless, I cannot actually provide a reference to the identification (II) of the $E^2$-term. The only textbook I found which referred to local coefficients in the Serre spectral sequence was the aforementioned book by May and Ponto, but they assume $B$ is pointed (and connected), and do not appear to prove a natural isomorphism for the $E^2$-term. Can anyone provide a reference, or otherwise point out my error?

Indispensably, the fibre of the Serre fibration did not actually figure into the above construction of the Serre spectral sequence. In fact, the fibres only make an appearance once one tries to compute the $E^2$-term. Nevertheless, one can also identify the $E^2$-term in this general case, and moreover, in a functorial manner. The $E^2$-term of the general Serre spectral sequence described above is naturally isomorphic to (which I write here as equal) $$ E^2_{p,q}=H_p(B,H_q(F_\bullet)) \qquad\qquad \text{(II)} $$ with the naturality holding with respect to Serre fibrations $f:E\to B$, and maps of Serre fibrations. Here is a description of the right hand side of (II). Let $F_x=f^{-1}(x)$ be the fibre of $f$ over $x\in B$. In the above expression, $H_q(F_\bullet)$ represents the system of local coefficients on $B$ corresponding to the functor $$ H_q(F_\bullet):\Pi_1(B)\To\Ab $$ from the fundamental groupoid of $B$ to the category of abelian groups. This functor takes a point $x\in B$ to $H_q(F_x)$, and a path homotopy class $[\gamma]$ of paths in $B$ to the map induced by the monodromy along $\gamma$ on the homology of the fibres over the endpoints of $\gamma$. Then the right hand side of (II) is the homology of $B$ for this system of local coefficients. It is straightforward to check this homology is indeed functorial with respect to maps of Serre fibrations.

Disclaimer: I believe (note the emphasis) that the above functorial identification of the $E^2$-term follows the same recipe as the usual derivation of the isomorphism (I) when $B$ is pointed and the fibration is orientable (conditions 1 and 2 above). To be honest, I have not carefully checked the details myself! Please let me know if I am in error. It appears to be considered folklore knowledge. Nevertheless, I cannot actually provide a complete reference to the identification (II) of the $E^2$-term. The only textbooks I have found which refer to local coefficients in the Serre spectral sequence are the aforementioned book by May and Ponto, and McCleary's A user guide to spectral sequences. The former skips the proof in the general case, but at first sight the proof in McCleary's book does seem to give (II) as a natural isomorphism, even if the result is not stated explicitly. Can anyone provide a better reference?