I did at least half of the work, I am not cited in the presentations For some context, I am enrolled in a PhD in applied mathematics.

There is a recent work where I, my thesis adviser and a friend of his in industry have worked together, with at least half of the work done by me, I even tutored the colleague to help him start at the beginning. 

This work got presented by the two of them at different conferences. Each time I wasn't cited at the presentations (except just once when my adviser decided to put my name in the first slide, but the colleague then uploaded an identical version without my name). My adviser still gives me credit whenever he exchanges with attendants or other academics, and yes I got my name on the paper, but two things still bother me:


the colleague never mentions me, he remorselessly talks about the work as being his and my adviser's only (he can't easily get rid of my adviser since he's well known, but at least he can get rid of me and no one would notice), the damage is beyond just talk as he also writes that in his updates to his network;
being a PhD student or not, and even if my name is on the paper, removing it from the presentations is unfair and damaging and just feeds the idea that maybe my name is on the paper just because I did secondary work or scripting/plotting.


This kept happening for a few months now and will keep going if this issue is not addressed as my adviser and his colleague keep submitting the work to future conferences. Some might see me as overreacting but this is impacting me in a lot of ways and the feeling of betrayal is hitting hard, I even stopped working with my adviser's colleague altogether without notice and started pursuing some of my own research goals alone without notifying anyone of my progress.

I just started my PhD half a year ago, so surely I may be lacking experience with regards to these issues of authorship and citation, but is it common practice to assume that a PhD student should just be content with his name being in a paper, but not expect to be cited when the work is presented in conferences, even if he put more than half of all the combined work? What would be the motivation of keeping me out during conferences ? Better to split the cake in two rather than three ? Should I bring this up with my thesis adviser even though the one who is clearly dishonest here is a friend of his?
It definitely sucks when you feel like you're not getting credit for your work, and in applied math, it is certainly not standard practice to omit mention of PhD students' contributions.  In fact, I've seen many presentations where professors and industry leaders show group pictures of their entire lab, and they're proud of the team effort.

However, passive aggression is almost never effective at helping you achieve what you want.

You seem to be on better footing with your supervisor than with his colleague, so I would start there.  Once you've cooled off a bit, schedule a meeting with him and mention how you've noticed your name is absent from presentations on your work.  Be honest (and respectful) about how this hurts you, and leave room for your advisor to explain.  It could just be an honest oversight, it may be intentional-- the fact is, you don't have anything but speculation until he explains.  Mention that you've noticed the same happens with his colleague's presentations, and ask if he could talk to the guy about it.  Again, try not to assume the worst.  There isn't any real motivation for omitting someone's name when they've made serious contributions, especially in industry, where large author counts are the norm and papers don't matter nearly as much as they do in academia.