"Codomain and range are not the same" - Umm. Interesting. Not aware of this. "I learned about 'one-to-one and onto' functions instead of 'bijective' functions"

"Codomain and range are not the same" - Umm. Interesting. Not aware of this. "I learned about 'one-to-one and onto' functions instead of 'bijective' functions" - For a beginner? The former. Past beginner? The latter. It's context. The "strange symbols" I only came across when searching for are described as double-struck. I only found that recently. I only found out yesterday they were also called Blackboard, while replying to others here. Difficulty in finding symbol meanings are no way the hard part of maths, though.