[Tex/LaTex] Why is the text going over the margin

margins

I have written a paragraph of text and one line is protruding out into the right margin. I am completely baffled, can anyone help?

My text is thus

"… cohomology of the base manifold. These invariants describe the obstruction to the presence of global sections, which we may interpret as a measure of the twisting of a bundle.

Today there are three main expositions of characteristic classes: Chern-Weil theory; the approach of Grothendieck; and the study of universal bundles. Each exposition has its merits and its drawbacks, and we shall not have time to present all three. We will focus initially on the Chern-Weil approach as presented in Madsen \& Tornehave \cite{Madsen} in which characteristic classes are derived by taking invariant polynomials in the curvature form, a construction well studied in differential geometry. This approach is preferred as it leads to simple proofs of the important naturality and Whitney-sum properties. We will then discuss briefly the approach of Grothendieck as presented in Bott \& Tu \cite{Bott} which deserves attention simply for its elegance. Here a class is constructed for a rank 2, oriented vector bundle, living in the cohomology of the base manifold, which is seen to pull back its information from the fibre above, counting the number of obstructions to the presence of a global section. Then, using the Leray-Hirsch theorem and some clever algebra as well as a result from cohomology, characteristic classes are derived from this for general complex vector bundles. This approach allows us to present a clear computation.

Neither of these first two expositions really address the important question of {\textit{why}} such characteristic classes…"

And here's how it is coming out!

enter image description here

Any ideas?

Thanks,
Adam.

Best Answer

There are several possibilitys to solve your problem.

Because you gave no MWE I created a simple one (I left out your cites, say you will see ? instead) and used package geometry to get the layout you showed in your picture. (Remark: It would be easier next time you provide such a MWE by your own, please!)

I added package showframe to show the typing area.

Then I added command \hyphenation{Gro-then-dieck} to show that only this command will give you the result you want.

But you do not need \hyphenation if you use package microtype. Only with microtype you get in this example a proper justifing left and right without a hyphenation of Grothendieck. (Play with the margins in geometry and you will get situations that an hyphenation occurs.)

I suggest to call package microtype in all your documents.

MWE (with activated microtype; comment it and uncomment the line for hyphenation to test the other version; comment both to have your situation):

\documentclass{article}

\usepackage[margin=2.2cm]{geometry}
\usepackage{showframe}

 \usepackage{microtype}      % <=========================================
%\hyphenation{Gro-then-dieck}% <=========================================


\begin{document}
... cohomology of the base manifold. These invariants describe the 
obstruction to the presence of global sections, which we may interpret 
as a measure of the twisting of a bundle.

Today there are three main expositions of characteristic classes: 
Chern-Weil theory; the approach of Grothendieck; and the study of 
universal bundles. Each exposition has its merits and its drawbacks, 
and we shall not have time to present all three. We will focus initially 
on the Chern-Weil approach as presented in Madsen \& Tornehave 
\cite{Madsen} in which characteristic classes are derived by taking 
invariant polynomials in the curvature form, a construction well studied 
in differential geometry. This approach is preferred as it leads to 
simple proofs of the important naturality and Whitney-sum properties. 
We will then discuss briefly the approach of Grothendieck as presented 
in Bott \& Tu \cite{Bott} which deserves attention simply for its 
elegance. Here a class is constructed for a rank 2, oriented vector 
bundle, living in the cohomology of the base manifold, which is seen to 
pull back its information from the fibre above, counting the number of 
obstructions to the presence of a global section. Then, using the 
Leray-Hirsch theorem and some clever algebra as well as a result from 
cohomology, characteristic classes are derived from this for general 
complex vector bundles. This approach allows us to present a clear 
computation.

Neither of these first two expositions really address the important 
question of {\textit{why}} such characteristic classes ...
\end{document}

and the result:

enter image description here

and with both uncommented lines you get an hyphenation in Grothendieck:

enter image description here

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