I want to define an abbreviation, for example, \newcommand{\pca}{Principal Component Analysis}. It seems trivial, but I am unable to do it. Please see below the code snippet-
\documentclass{article}
% define an abbreviation
\newcommand{\pca}{Principal Component Analysis}
\begin{document}
\pca is an unsupervised, non-parametric statistical technique primarily in machine learning. The dimensionality reduction can be done using \pca.
\end{document}
Below is a screenshot of the generated output-
It can be seen that there is no space between "analysis" and "is" as highlighted in the screenshot above.
Adding a space intentionally using \pca~is could be a workaround, but I believe there must be a better way. Please suggest.

~or\or {}to get the space. (~` prevents line breaking) – David Carlisle May 19 '20 at 13:21\pca{}is working fine. But can't we omit parenthesis just like\alpha,\beta,\gamma, etc.? – ravi May 19 '20 at 13:21\alphaexcept that spaces are ignored in math, in math$a b$is the same as$ab$but in text you need the space. – David Carlisle May 19 '20 at 13:24\pca{}looks like passing no arguments to it, (although the command\pcais already defined to take no arguments). – ravi May 19 '20 at 13:26{\itshape this is italic} this not{}don't always mean arguments in tex – David Carlisle May 19 '20 at 13:29