# Why is my text going over the margin?

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!

Any ideas?

• The possible solutions here are varied and are covered on this site. You can either print this as a \begin{sloppypar}...\end{sloppypar}, or define a specific hyphenation pattern for Grothendieck using \hyphenation{Gro-then-dieck} or use it inline Gro\-then\-dieck.
– Werner
Mar 11, 2015 at 19:10
• Force hyphenation writing Gro\-then\-dieck. Mar 11, 2015 at 19:10
• add this to your preamble: \hyphenation{Grothen-dieck}; then it will be available everywhere in your document, not just in this one place. Mar 11, 2015 at 20:30
• @barbarabeeton Grothendieck is treated worse than Dr. Treemunch! At least the latter gets a (wrong) hyphen! Mar 11, 2015 at 22:13
• It's not surprising that Grothendeick can't be split:)
– user30471
Mar 12, 2015 at 11:22

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:

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

• I see no conflict in providing the instruction \hyphenation{Gro-then-dieck} and loading the microtype package.
– Mico
Oct 9, 2015 at 5:24
• Your sentence “But you do not need \hyphenation” is, at the least, misleading: \hyphenation{Gro-then-dieck} is not needed in this particular case. Other paragraphs might need it also with microtype loaded. Oct 9, 2015 at 9:03