# How to remove white spaces before a table

I have the following code, but I am unable to remove the white space before the table even after using \vspace{} right after \subsection{Nomenclature}.

\section{Mathematical Modeling}

In this section we present the mixed integer linear programming (MILP) models that form the basis of decision-making and the subsequent computational testing. We first present a listing of notation used, then we present the UC-SOC model that corresponds to current practice / state-of-the art benchmark, and finally we present the new model being proposed in this paper.

\subsection{Nomenclature}\label{nom}
\vspace{-6.17mm}
\begin{table}[H]
\begin{tabular}{>{$}l<{$} l}
\multicolumn{2}{l}{\textit{A. Indices and Sets}}\\
\\
t & Index of time period, with  $t \in T$, the set of time periods.\\
s &Index of supplier, with $s \in S$, the set of suppliers .\\
j &Index of customer, with $j \in J$, the set of customers.\\
k &Index of attribute,  with $k \in K$, the set of attributes, $k$ = 1 denotes fixed payment,\\
& $k$ = 2 denotes variable payment, $k$ = 3 denotes interruption ceiling.\\
%k =1 denotes fixed payments to customers,\\
%k =2 denotes interruption ceiling.\\ %need to find out 5_12
\ell_k &Index of level of $k^{th}$ attribute, with $\ell_k$ $\in$ $L_k$, the set of levels for attribute $k$.\\%need to find out 5_12
SOC &Set of SOC customers\\
\\
\end{tabular}
\end{center}
\end{table}

• Your example document is missing the \begin{tabular}. Please, make sure that the document is compilable (add the mandatory \documentclass and the relevant \usepackages). Also, the center environment adds extra vertical spacing, you shouldn't use it in floats (e.g. table and figure), change to \centering. And you have two consecutive \\ , which will create an empty line in the table. – Phelype Oleinik Sep 27 '18 at 19:17
• note that you are using [H] by design [H] introduces large white space in documents as it disables the floating mechanism and the only reason that tables float is to avoid bad white space around page breaks. – David Carlisle Sep 27 '18 at 19:21
• unrelated but  $k$ = 1  should be  $k = 1$ – David Carlisle Sep 27 '18 at 19:27
• Same goes for $k$ = 1 and $\ell_k$ $\in$ $L_k$ should be $k = 1$ and $\ell_k \in L_k$. – Skillmon likes topanswers.xyz Sep 27 '18 at 19:28

It's a common misunderstanding that a tabular has to go in a table environment. This is not true, it can go anywhere.
3. Most entries in the first column should be between $ signs 4. $k$= 1 should be $k=1$ 5. $k^{th}$ should be $k$\textsuperscript{th} or, better, $k$th 6. $\ell_k\inL_k$ should be a single formula $\ell_k\in L_k$ Here's the code, I just guessed a value for the width of the second column. \documentclass{article} \begin{document} \section{Mathematical Modeling} In this section we present the mixed integer linear programming (MILP) models that form the basis of decision-making and the subsequent computational testing. We first present a listing of notation used, then we present the UC-SOC model that corresponds to current practice/state-of-the art benchmark, and finally we present the new model being proposed in this paper. \subsection{Nomenclature}\label{nom} \begin{center} \begin{tabular}{lp{.5\textwidth}} \multicolumn{2}{l}{\textit{A. Indices and Sets}}\\ \\$t$& Index of time period, with$t \in T$, the set of time periods.\\$s$& Index of supplier, with$s \in S$, the set of suppliers.\\$j$& Index of customer, with$j \in J$, the set of customers.\\$k$& Index of attribute, with$k \in K$, the set of attributes,$k = 1$denotes fixed payment,$k = 2$denotes variable payment,$k = 3$denotes interruption ceiling.\\$\ell_k$& Index of level of$k$\textsuperscript{th} attribute, with$\ell_k\in L_k$, the set of levels for attribute$k$.\\ SOC & Set of SOC customers\\ \end{tabular} \end{center} \end{document}  Thanks to all. The following solution worked. Please note that additional blank lines in the table (\\) were removed and \centering was used instead of center. \subsection{Nomenclature}\label{nom} \begin{table}[H] \centering \begin{tabular}{>{$}l<{$} l}%for math mode in table \multicolumn{2}{l}{\textit{A. Indices and Sets}}\\ %\\ t & Index of time period, with$t \in T$, the set of time periods.\\ s &Index of supplier, with$s \in S$, the set of suppliers .\\ j &Index of customer, with$j \in J$, the set of customers.\\ k &Index of attribute, with$k \in K$, the set of attributes,$k= 1 $denotes fixed payment,\\ &$k = 2$denotes variable payment,$k = 3$denotes interruption ceiling.\\ %k =1 denotes fixed payments to customers,\\ %k =2 denotes interruption ceiling.\\ %need to find out 5_12 \ell_k &Index of level of$k$\textsuperscript{th} attribute, with$\ell_k \in L_k$, the set of levels for attribute$k\$.\\%need to find out 5_12
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